do by halves

Verb

 * 1)  To perform (a task, etc) partially or incompletely; to do (something) inadequately, halfheartedly, or shoddily.
 * 2) * 1925 Sept. 21, Mordaunt Hall, "The Screen" (film review of The Freshman), New York Times (retrieved 5 March 2014) :
 * Rin-Tin-Tin does nothing by halves, for he tracks the murderer himself and kills him.
 * Rin-Tin-Tin does nothing by halves, for he tracks the murderer himself and kills him.