NULLITY Meaning of NULLITY in English nul ‧ li ‧ ty /ˈnʌləti, ˈnʌlɪti/ BrE AmE noun [uncountable] law the fact that a marriage or contract no longer has any legal force:a decree of nullity Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012