The Collaborative International Dictionary
gun for
gun for \gun for\, v. t.
To pursue with the intent to kill.
Fig. To make an effort to harm someone, especially with determination; -- also used humorously.
Wiktionary
gun for
vb. 1 (context transitive English) To strive for the downfall or diminution of another. 2 (context transitive English) To pursue as a goal; to work hard to achieve.
Usage examples of "gun for".
He passes a boxed pair of Number 4 Derringers, be a nice gun for Jeanine, she could tuck it in her G-string, fire off a shot with every bump and grind.