苦幹

to work hard

bitter / hardship / pain / to suffer / to bring suffering to / painstakingly

tree trunk / main part of sth / to manage / to work / to do / capable / cadre / to kill (slang) / to fuck (vulgar) / (coll.) pissed off / annoyed

to bury oneself in work (idiom); to be engrossed in work / to make an all-out effort / up to the neck in work