Barely sufficient examination taking minimal time (5)
I believe the answer is:
scant
'barely sufficient' is the definition.
(I've seen this before)
'examination taking minimal time' is the wordplay.
'examination' becomes 'scan' (scan is a kind of examination).
'taking' says to put letters next to each other.
'minimal' indicates taking the first letters.
The initial letter of 'time' is 't'.
'scan'+'t'='SCANT'
(Other definitions for scant that I've seen before include "Cursory" , "Meagre" , "Barely adequate" , "Reduce" , "Deficient, sparing" .)