Drinks in middle of week? Pass (6)
I believe the answer is:
elapse
'pass' is the definition.
(I've seen this before)
'drinks in middle of week?' is the wordplay.
'drinks' becomes 'laps' (lapping is a kind of drinking**).
'in' means one lot of letters goes inside another.
'middle of' says to take the centre.
The central letters of 'week' are 'ee'.
'laps' put inside 'ee' is 'ELAPSE'.
(Other definitions for elapse that I've seen before include "(Of time) go by" , "Of time, pass by - please" , "Pass away - asleep (anag)" , "run by" , "Slip away" .)