Behind schedule, learner driver worried (4)
I believe the answer is:
late
'behind schedule' is the definition.
(I've seen this before)
'learner driver worried' is the wordplay.
'learner driver' becomes 'l' (I've seen this in other clues).
'worried' becomes 'ate' (something worrying may eat someone up).
'l'+'ate'='LATE'
(Other definitions for late that I've seen before include "Delayed; dead" , "Yet to arrive?" , "After the usual time" , "Dead or not punctual" , "Far into the night" .)