Unfortunately I'm no dad, but good bloke (7)
I believe the answer is:
diamond
'good bloke' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'unfortunately i'm no dad' is the wordplay.
'unfortunately' indicates anagramming the letters (a bad or unfortunate spelling).
'im'+'no'+'dad'='imnodad'
'imnodad' with letters rearranged gives 'DIAMOND'.
'but' acts as a link.
Can you help me to learn more?
(Other definitions for diamond that I've seen before include "Very hard gem" , "Gem stone" , "Kohinoor, Hope" , "One of her best friends" , "nickname of US State" .)