compulsory (adj.)

• absolute
• binding
• compelling
• compulsive
• conclusive
• constraining
• decisive
• dictated
• driving
• exigent
• final
• hard-and-fast
• imperative
• imperious
• importunate
• imposed
• inevitable
• involuntary
• irresistible
• irrevocable
• mandatory
• must
• necessary
• necessitous
• obligatory
• peremptory
• prescriptive
• pressing
• required
• restraining
• ultimate
• urgent