Crossword Genius

Caustic - like metal? (6)

Ross

I believe the answer is:

ironic

I'm a little stuck... Click here to teach me more about this clue!

'caustic' is the definition.
(thesaurus)

'metal?' is the wordplay.
I cannot quite see how this works, but
'metal?' could be 'ni' (Ni is an example) and 'ni' is found in the answer.
The remaining letters 'iroc' is a valid word which might be clued in a way I don't understand.
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" .)

I've seen this clue in The Mirror.
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