Stupid reply, ignoring wife at home alone at last (8)
I believe the answer is:
'stupid' is the definition.
(similar in meaning)
'reply ignoring wife at home alone at last' is the wordplay.
'reply' becomes 'ans' (abbreviation for answer).
'ignoring wife' becomes 'er' (I can't explain this - if you can you should give a lot more credence to this answer).
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'at last' says to take the final letters.
The last letter of 'alone' is 'e'.
Can you help me to learn more?
(Other definitions for anserine that I've seen before include "Silly" , "Like a goose" , "Foolish" .)