If you describe a man as a yes-man, you dislike the fact that he seems always to agree with people who have authority over him, in order to gain favour.
[disapproval]
yes man in British English
noun
a servile, submissive, or acquiescent subordinate, assistant, or associate; sycophant
yes man in American English
US
Slang
a person who gives undiscriminating approval to every suggestion or opinion offered by a superior
Examples of 'yes man' in a sentence
yes man
To be sure, this skepticism of the yes-man mentality has advantages.
Christianity Today (2000)
He was a huge yes-man.
Times, Sunday Times (2010)
The no-man is just as bad as the yes-man, though.
Times, Sunday Times (2016)
Becoming a fat, dull, yes-man seemed too big a price to pay.
Times, Sunday Times (2010)
We can change everything but the weather,' the yes-man says with a smile.