Caustic - like metal? (6)
I believe the answer is:
ironic
'caustic' is the definition.
(thesaurus)
'metal?' is the wordplay.
I cannot really see how this works, but
'metal?' could be 'iron' (iron is a kind of metal) and 'iron' is found within the answer.
This explanation may well be incorrect...
'like' is the link.
Can you help me to learn more?
(Other definitions for ironic that I've seen before include "Wryly funny" , "Characterised by mildly sardonic wit" , "Sarcastically humorous" , "'Wry, incongruous (6)'" , "Sarcastic, expressing meaning by invoking opposite" .)