Moan at splinters without exception (2,1,3)
I believe the answer is:
to a man
'without exception' is the definition.
(synonyms)
'moan at splinters' is the wordplay.
'splinters' is an anagram indicator (I've seen 'splintered' mean this).
'moan'+'at'='moanat'
'moanat' with letters rearranged gives 'TO A MAN'.
(Other definitions for to a man that I've seen before include "Unopposed" , "All without exception - excluding women?" , "All united-males only?" , "all of us" .)