Free for part of Friday (3)
I believe the answer is:
rid
'free' is the definition.
(to be free of something is to be rid of it)
'part of friday' is the wordplay.
'part of' indicates a hidden word.
'RID' is hidden in the letters of 'friday'.
'for' acts as a link.
(Other definitions for rid that I've seen before include "Lose, shake off" , "Free, disencumber" , "Disabuse" , "Throw off, unburden" , "Free, relieve" .)