Did an evening job, flat out (6)
I believe the answer is:
ironed
'flat out' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'did an evening job' is the wordplay.
I cannot really see how this works, but
'an' could be 'one' and 'one' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ironed that I've seen before include "Smoothed the cloth with heat" , "Decreased?" , "Got rid of creases" , "Had an evening out" , "flattened" .)