stag

nouns

a male deer, especially an adult male red deer
hart, stag
adult male deer
stag
is a type of (narrower)
mature male of various mammals (especially deer or antelope)
buck

verbs

attend a dance or a party without a female companion
stag
give away information about somebody
"He told on his classmate who had cheated on the exam"
betray, denounce, give away, grass, rat, shit, shop, snitch, stag, tell on
watch, observe, or inquire secretly
sleuth, snoop, spy, stag