Breather required before everyone’s third jab (5)
I believe the answer is:
lunge
'jab' is the definition.
(thesaurus)
'breather required before everyone's third' is the wordplay.
'breather' becomes 'lung' (you breathe with your lungs).
'required before' says to put letters next to each other.
'everyone's third' becomes 'e' (3rd letter of 'everyone').
'lung'+'e'='LUNGE'
(Other definitions for lunge that I've seen before include "foil attack?" , "Sudden forward move" , "Sudden move forwards" , "Stab" , "Sudden thrust in fencing" .)