From Malay ajar, from Sanskrit आचार्य (ācārya, “teacher, master”), likely derived from आचार (ācāra, “conduct, behavior”).

What is ajar derived from?

ajar (adv.)

"on the turn (of a door or gate)," from Middle English char "a turn," from Old English cier "a turn" (see chore). For first element see a- (1).

What does ajar mean?

: slightly open left the door ajar.