• assiduous, dutiful, obedient, to be unfailing in one's duty
• breach of duty, lapse from duty
• delinquency, dereliction of duty, nonfeasance
• consonant with one's duty
• to be bound to do sg, to be supposed to do sg
• I consider it my duty to
• to be unfailing in one's duty
• to deliver the goods, to fulfil one's obligation, to meet one's obligation