Blast! Mother has got into an awful mess! (9)
I believe the answer is:
damnation
'awful mess' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'blast mother has got into an' is the wordplay.
I cannot quite see how this works, but
'blast' could be 'damn' (I've seen this before) and 'damn' is located in the answer.
an anagram of 'into' is 'tion' which is within the answer.
'an' could be 'a' and 'a' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for damnation that I've seen before include "Cursing" , "Eternal punishment" , "angry exclamation?" , "Denouncing" , "Mild oath" .)