trivial matter; trifle; unimportant thing
Refers to something insignificant or not worth serious attention. Often used in negative contexts to dismiss something as unimportant.
That's a trivial matter.
He doesn't get hung up on trifles.
Compound of 徒 (あだ, 'vain, futile') and 事 (こと, 'matter, thing'). The reading あだごと is a rendaku form of こと.