How one talks with a caustic wit? (6)
I believe the answer is:
acidly
'how one talks with a caustic wit?' is the definition.
I can't tell whether this defines the answer.
'with a caustic wit?' is the wordplay.
'with' says to put letters next to each other.
'a caustic' becomes 'acid' (I've seen this before).
'wit?' becomes 'ly' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'acid'+'ly' is 'ACIDLY'.
Can you help me to learn more?
(Other definitions for acidly that I've seen before include "in a sour manner" , "in caustic manner" , "Bitterly" .)