na-adjective
difficult-looking; hard-seeming; troublesome; serious-looking
Describes something that appears difficult, complicated, or serious. Often used for problems, situations, or expressions. The げ suffix adds a nuance of 'seeming' or 'appearing'.
彼は難しげな顔で考え込んでいた。
He was deep in thought with a difficult-looking expression.
この問題は難しげに見えるけど、実は簡単だ。
This problem looks difficult, but it's actually easy.