From Longman Dictionary of Contemporary Englishonce and for allonce and for alla) CHANGE/MAKE something DIFFERENTif you deal with something once and for all, you deal with it completely and finally Let’s settle this matter once and for all. b) British English spokenTELL/ORDER somebody TO DO something used to emphasize your impatience when you ask or say something that you have asked or said many times before Once and for all, will you switch off that television! → once
Examples from the Corpus
once and for all• Let's settle this matter once and for all.• I was perilously close to being touched once and for all.• Only by exploring these patterns, their causes and effects, is there any possibility of breaking them once and for all.• This was supposed to be her final victory over him, supposed to establish her rule once and for all.• Three blocks south, fancier houses in the 700 block of Commercial Street were shuttered once and for all.• Jackson proved once and for all he was no longer the kid star of the Jackson Five days.• Seismic tomography showed once and for all that the mantle was indeed in motion.• I had to destroy, once and for all, the vicious circle of poverty and economic stagnation.• No magic wand exists that can be waved once and for all to end injustice. 