Indicates dissent to person suggesting this is an island? (5)

I believe the answer is:

noman

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

'this is an island?' is the definition.
The definition suggests a singular noun which matches the answer.

'indicates dissent to person' is the wordplay.
'indicates dissent' becomes 'no' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to person' becomes 'man' (man is a kind of person).
'no'+'man'='NOMAN'

'suggesting' acts as a link.

Can you help me to learn more?

(Another definition for noman that I've seen is " ' - - is an Island' (Donne)".)

I've seen this clue in The Irish Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.