attentive (adj.)

c. 1300, "be subject to" (obsolete); early 14c., "direct one's mind or energies" (archaic), from Old French atendre "to expect, wait for, pay attention" (12c., Modern French attendre) and directly from Latin attendere "give heed to," literally "to stretch toward," from ad "to, toward" (see ad-) + tendere "stretch" (from PIE root *ten- "to stretch"). The notion is of "stretching" one's mind toward something.

The sense of "take care of, wait upon" is from mid-14c.; that of "endeavor to do" is from c. 1400. The meaning "to pay attention" is from early 15c.; that of "accompany and render service to" (someone) is from mid-15c., as is that of "be in attendance." The meaning "to accompany or follow as a consequent" is from 1610s. Related: Attended; attending.

"heedfulness, attention. state of being attentive," mid-15c., from attentive + -ness.

"heedless, careless, negligent," 1650s, from in- (1) "not, opposite of" + attentive. Related: Inattentively; inattentiveness.