Call up the day before about fair (5)
I believe the answer is:
evoke
'call up' is the definition.
('evoke' can be a synonym of 'call up')
'the day before about fair' is the wordplay.
'the day before' becomes 'eve' (I've seen this before).
'about' indicates putting letters inside.
'fair' becomes 'ok'.
'eve' placed around 'ok' is 'EVOKE'.
(Other definitions for evoke that I've seen before include "Awaken memories in the mind" , "Call up; elicit" , "Call up memories of feelings" , "Induce" , "Recall" .)