Crossword Genius

Mud, Fijian perhaps, lacks iodine (7)

Ross

I believe the answer is:

slander

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

This might be a double definition.

'mud fijian' is the first definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?

'lacks iodine' is the second definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'perhaps' is the link.

Can you help me to learn more?

(Other definitions for slander that I've seen before include "Malicious gossip" , "False/malicious speech" , "Malicious speech" , "False or malicious report" , "Damaging statements" .)

I've seen this clue in The Times and The Sunday Times.
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