Fair enough! (8)
I believe this clue is a double definition.
'fair' is the first definition.
(synonyms)
'enough' is the second definition.
(I know that enough can be written as adequate)
(Other definitions for adequate that I've seen before include "Sufficient, good enough" , "'Satisfactory, acceptable (8)'" , "'Good enough, all right (8)'" , "Enough to meet a purpose" , "up to the job?" .)
(Other definitions for touche that I've seen before include "cry from fencer" , "Acknowledgment of a hit in fencing" , "Acknowledgment of hit by fencer" , "Fencing call" , "You got me" .)