undertip 
verb (undertips, undertipping, undertipped) [with object]
Give (someone) an excessively small tip: I was so mad I undertipped the waiter at the sushi bar...
- Oh my gosh, I've been undertipping my hairstylist.
- gentleman's C
- gentleman's gentleman
- Gentleman's Relish
- Gentleman Usher of the Black Rod
- gentlemen's agreement
- gentlemen's C
- gentleness
- gentlepeople
- gentlewoman
- gently
- gently born
- gentoo
- gentoo penguin
- gentrification
- gentrifier
- gentrify
- gentry
- genu
- genuflect
- genuflection
- genuflector
- genuine
- genuinely
- genuineness
- genus