Parsnip oddly lacking flavour at first? Yeah, right! (4)
I believe the answer is:
asif
'yeah right' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'parsnip oddly lacking flavour at first?' is the wordplay.
'oddly lacking' means one should take alternating letters (letters in odd-numbered positions removed).
'at first?' suggests taking the first letters (I've seen 'at first' mean this).
The initial letter of 'flavour' is 'f'.
The alternating letters of 'parsnip' are 'asi'.
'asi'+'f'='ASIF'
Can you help me to learn more?
(Other definitions for asif that I've seen before include "I very much doubt it!" , "yeah, right!" , "Common name in Pakistan" .)