Level in rugger, having lost every other one — win following defeat? (7)
I believe the answer is:
revenge
'win following defeat?' is the definition.
(revenge might be a victory after a previous defeat)
'level in rugger having lost every other one' is the wordplay.
'level' becomes 'even' (similar in meaning).
'in' means one lot of letters goes inside another.
'having lost every other one' means one should take alternating letters (every other letter is removed).
The alternate letters of 'rugger' are 'rge'.
'even' inserted inside 'rge' is 'REVENGE'.
(Other definitions for revenge that I've seen before include "Malicious retaliation" , "Retribution" , "Satisfaction taken for injury" , "Ship remembered in verse" , "An eye for an eye" .)