Old pair of females absent (3)
I believe the answer is:
off
'absent' is the definition.
(thesaurus)
'old pair of females' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'pair of' indicates the doubling of some letters (I've seen 'pair' mean this).
'females' becomes 'f' (this might be a standard abbreviation of which I'm unaware).
'f' duplicated is 'ff'.
'o'+'ff'='OFF'
(Other definitions for off that I've seen before include "away from the kerb" , "below par" , "Away, at a distance" , "Gone - bad" , "(Of food) no longer fresh" .)