de rigueur (adj.)

• accepted
• acknowledged
• approved
• becoming
• binding
• conformable
• conventional
• correct
• customary
• decent
• decorous
• done
• formal
• imperative
• imperious
• mandatory
• meet
• must
• necessary
• nice
• obligatory
• orthodox
• peremptory
• proper
• received
• recognized
• required
• right
• seemly
• traditional