Suggest liqueur is lacking a bit of excitement (8)
I believe the answer is:
advocate
'suggest' is the definition.
(advocating is a kind of suggesting)
'liqueur is lacking a bit of excitement' is the wordplay.
I cannot really understand how this works, but
'a' is within the answer.
'bit' could be 'ate' ('bite' can be similar in meaning to 'eat') and 'ate' is located in the answer.
'of' could be 'o' and 'o' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for advocate that I've seen before include "Defender" , "Recommend - lawyer" , "One argues another's case" , "Publicly support (cause)" , "Argue for" .)