1. To give (someone or something) little bites. Their dog kept nipping on my heels whenever I walked through the house.I felt some nipping on my toes during the night, and I absolutely freaked out
2. To take small, frequent sips of some drink, especially alcohol. I caught my grandma nipping on a flask, which she tried to pretend had medicine inside of it.He nipped at a bottle of whiskey to help keep warm as he trudged through the snow.
nip on
v.
1. To grab and pinch or bite: The fish nipped on the wader's feet.
2. To sip some drink, often alcoholic, in small amounts: The guests nipped on their eggnog all night long. I nipped on my soda while waiting for my date to show up.