Pair with female in a barely believable embarrassing mistake (8)
I believe the answer is:
pratfall
'embarrassing mistake' is the definition.
(I've seen this before)
'pair with female in a barely believable' is the wordplay.
'pair' becomes 'pr' (abbreviation).
'with' means one lot of letters go next to another.
'female' becomes 'f' (abbreviation).
'in' indicates putting letters inside.
'a barely believable' becomes 'atall' (I can't explain this - if you can you should give a lot more credence to this answer).
'f' inserted into 'atall' is 'atfall'.
'pr'+'atfall'='PRATFALL'
Can you help me to learn more?
(Other definitions for pratfall that I've seen before include "Embarrassing mistake" , "Slip" , "humiliating blunder" , "Humiliating failure (US slang)" , "embarrassment" .)