godan verb (-su), transitive verb
Causative meaning: to let or make someone do something. Often used in casual speech as a shorter alternative to やらせる. The nuance between 'let' and 'make' depends on context.
See also: 遣らせる
子供に好きなだけ遊ばせてやらす。
I let the kids play as much as they want.
I can't let you do that.