stag

(noun) a male deer, especially an adult male red deer. Synonyms: hart.

(noun) adult male deer.

(verb) attend a dance or a party without a female companion.

(verb) give away information about somebody. Synonyms: denounce, tell on, betray, give away, rat, grass, shit, shop, snitch. Examples: "He told on his classmate who had cheated on the exam."

(verb) watch, observe, or inquire secretly. Synonyms: spy, snoop, sleuth.