Middle English, from Latin aptus, literally, fastened,
from past participle of apere to fasten; akin to Latin apisci to grasp, obtain, apud near, Hittite hap- to attach
1 : unusually fitted or qualified : READY
2 a : having a tendency : LIKELY b : ordinarily disposed : INCLINED
3 : suited to a purpose; especially : being to the point
4 : keenly intelligent and responsive