1. at no time in the past or future; on no occasion; not ever: "they had never been camping in their lives"Similarat no timenot at any timenot evernot onceon no occasionliterary:ne'erOppositealwaysforever
2. not at all:"he never turned up"Similarnot at allcertainly notnot for a momentnot under/in any circumstancesunder/in no circumstanceson no accountinformal:no waynot on your lifenot in a million yearsnot for love or moneynot on your nellyOppositecertainlydefinitely
Word OriginOld Englishnǣfre, from ne ‘not’ + ǣfre ‘ever’.