painless

adjective

1 any killing of animals should be painless:

pain-free, under anaesthetic.

▷antonyms painful.

2 getting rid of him proved painless:

easy, trouble-free, effortless, undemanding, unexacting, simple, uncomplicated, smooth, plain sailing;

informal as easy as pie, as easy as falling off a log, as easy as ABC, a piece of cake, child's play, a cinch;

dated a snip.

▷antonyms difficult, demanding.

painless Oxford Dictionary of English