攻关

攻关	gōng guān	to storm a strategic pass / fig. to tackle a key problem
攻	gōng	to attack / to accuse / to study / (LGBT) top
关	Guān	surname Guan
关	guān	mountain pass / to close; to shut; to turn off / to confine; to lock (sb) up; to shut (sb in a room, a bird in a cage etc) / to concern; to involve