To drink without company proved a disaster (5-2)
I believe the answer is:
screw-up
'a disaster' is the definition.
(I've seen this before)
'to drink without company proved' is the wordplay.
I cannot quite understand how this works, but
'company' could be 'crew' (I've seen this before) and 'crew' is located in the answer.
'drink' could be 'sup' (to sup is to drink) and 'sup' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for screw-up that I've seen is " Disaster".)