discretion n.

"perceive or recognize the difference or distinction between (two or more things);" also "distinguish (an object) with the eyes, see distinctly, behold;" also "perceive rationally, understand;" late 14c., from Old French discerner (13c.) "distinguish (between), separate" (by sifting), and directly from Latin discernere "to separate, set apart, divide, distribute; distinguish, perceive," from dis- "off, away" (see dis-) + cernere "distinguish, separate, sift" (from PIE root *krei- "to sieve," thus "discriminate, distinguish"). Related: Discerned; discerning.

"left to discretion, restrained only by judgment," 1680s (implied in discretionarily); see discretion + -ary.

mid-14c., "want of discretion, imprudence," from Old French indiscrecion "foolishness, imprudence" (12c.), from Late Latin indiscretionem (nominative indiscretio) "lack of discernment," from in- "not, opposite of" (see in- (1)) + discretionem "discernment, power to make distinctions" (see discretion). Meaning "indiscreet act" is from c. 1600.