slysly /slaɪ/ adjective 
Word Origin
He leaned forward with a sly smile.3on the sly informal secretly, especially when you are doing something that you should not do: They’d been seeing each other on the sly for months.—slyly adverb—slyness noun [uncountable]
Word OriginWORD ORIGINsly
ExamplesOrigin:
1200-1300 Old Norse slgrEXAMPLES FROM OTHER DICTIONARIES
Thesaurus- A sly look crossed his face when Patsy mentioned the money.
- Children of that age can be very sly.
- Eliot looked sly and deceitful, as though he wasn't telling us the whole truth.
- He's a sly old devil isn't he! Nobody knew he had as much money as that!
- My parents didn't approve, but we continued to meet on the sly.
- The sly old Congressman knows what it takes to get elected.
- He wanted to forget that she was sly and spiteful and malicious.
- How the sly one squeaked, howled, sizzled, hissed, and swelled his hairy carapace!
- I began to dislike her; she looked sly and I felt indignant that she'd spoken to me like that.
- I won't be party to your bitching yourself on the sly.
- Manshin Anjima gave me a sly look and wrote down the name of her cemetery.
- Mitchell was shocked to see the man signaling him with sly winks.
THESAURUS► dishonest
Collocations behaving in a way that is intended to deceive people, for example by lying, cheating, or stealing: · Are you accusing me of being dishonest?· The money was acquired through dishonest means.· People are no longer surprised to find that politicians are dishonest.
► corrupt using your power in a dishonest way for your own advantage – used about people in official positions: · corrupt politicians· Law and order has broken down, and most government officials are corrupt.
► devious good at secretly thinking of clever plans to trick people in order to get what you want: · You have a very devious mind!· They use all kinds of devious methods to find out your personal details.
► underhand British English, underhanded American English underhand methods involve secretly deceiving people in order to get what you want: · In a series of underhand moves, Browne managed to gain control of the company.
► sneaky doing or saying things secretly, in a way that seems wrong because it is slightly dishonest or unfair: · It was pretty sneaky when the bank charged me interest on my account without telling me.
► sly deliberately behaving in a way that hides what you are really thinking or doing, in a way that is slightly dishonest: · Lucy decided not to tell him where she was going. She was often a bit sly like that.· He’s a sly old fox.
► unscrupulous using dishonest and unfair methods to get what you want, without caring if you harm other people: · Some unscrupulous companies try to persuade people to borrow huge sums of money.
► fraudulent formal deliberately deceiving people in an illegal way in order to gain money or power: · You will be prosecuted if you make a fraudulent claim on your insurance policy.
Longman Language Activatorsecretly dishonest► devious someone who is devious tries to get what they want by secretly using clever plans to trick people, so you can never be sure what their real intentions are: · You have to be pretty devious to be successful in that sort of business.· In the film, he plays a devious defence lawyer named Richard Adler.
► sneaky someone who is sneaky does things secretly and tricks people in order to get what they want: · You never know what's going on in that sneaky mind of his.· Watch out for Andy. He can be really sneaky.
► sly someone who is sly deliberately and cleverly hides their real intentions and feelings in order to get what they want, without other people realizing what they are doing: · Children of that age can be very sly.sly smile/look/expression etc: · A sly look crossed his face when Patsy mentioned the money.
► underhand British /underhanded American underhand methods or ways of doing things involve secretly deceiving people in an unfair way in order to get what you want without them knowing your intentions: · In a series of very smart, underhand moves, Browne gradually gained control of the company.· A federal judge criticized U.S. immigration officials for "underhanded tactics'' to deny asylum to Haitians.· She accused the council of behaving in an "underhand" manner and said residents should have been consulted.
clever in a dishonest or secret way► cunning a cunning person gets what they want by thinking carefully about it, making secret plans, and deceiving people: · Hawkeye was very cunning - he always waited until his enemy was alone and unarmed before making his attack.· She's a cunning little devil! She left for school as usual, and then went into town instead with her friends.
► sly a sly person secretly deceives people and is always thinking of ways to get advantages for themselves: · Eliot looked sly and deceitful, as though he wasn't telling us the whole truth. · He's a sly old devil isn't he! Nobody knew he had as much money as that!on the sly (=secretly and in a way that deceives people): · My parents didn't approve, but we continued to meet on the sly.
► crafty a crafty person is good at getting what they want by planning carefully and secretly deceiving people, often in a way that other people admire: · Jerry was crafty -- he got into the match free by crawling under the fence.· Crafty cyber-thieves have found that they can steal a lot of money in electronic bank thefts with very little risk.
► wily a wily person has had a lot of experience of getting what they want by tricking people, so that it is very difficult to trick them: · Breen had a reputation for being a tough and wily negotiator.· The Fawcett brothers were too wily to be caught, and the local residents could get no help from the law.
COLLOCATIONS FROM OTHER ENTRIES► a sly grin
Phrases· A sly grin crossed his face.
COLLOCATIONS FROM THE CORPUSNOUN► grin· A sly grin crossed his face as he thought of an alternative billet in which to spend what remained of the night.
► smile· Herbie's face had also lit in a sly smile as Mary had passed.· He was relieved when he saw Earnhardt's trademark sly smile.· Wickham saw Marshall's sly smile and understood what he was thinking.· By his sly smile, I think this is the one he intended.· All those gloating women looking down into his grave, whispering their sisterly secrets behind their sly smiles.
PHRASES FROM THE ENTRY► sly smile/glance/wink etc► on the sly
1someone who is sly cleverly deceives people in order to get what they want SYN cunning► see thesaurus at dishonest2sly smile/glance/wink etc a smile, look etc that shows you know something secret: - All those gloating women looking down into his grave, whispering their sisterly secrets behind their sly smiles.
- By his sly smile, I think this is the one he intended.
- He was relieved when he saw Earnhardt's trademark sly smile.
- Herbie's face had also lit in a sly smile as Mary had passed.
- Magrat took her seat and, to Agnes's amazement, gave her a sly wink.
- Mitchell was shocked to see the man signaling him with sly winks.
- Wickham saw Marshall's sly smile and understood what he was thinking.
- Dick had started drinking again on the sly.
- Elmer Gantry feels guilty for his vices: seeing people on the sly and drinking.
- He certainly wasn't dumping his pints on the floor on the sly.
- I won't be party to your bitching yourself on the sly.
- Sethe made a dress on the sly and Halle hung his hitching rope from a nail on the wall of her cabin.
- So we continued to meet on the sly.
- Sometimes she would give him money on the sly and he would help her with chores.
- The smartest girl passes answers on the sly to her table-mates.
- We try and slip him in on the sly when we think we've got them hooked.
He leaned forward with a sly smile.3on the sly informal secretly, especially when you are doing something that you should not do: They’d been seeing each other on the sly for months.—slyly adverb—slyness noun [uncountable]