One dwelling in Ontario, also Garda, oddly unseen? (5)

I believe the answer is:

naiad

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'one dwelling in ontario also garda oddly unseen?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

This is the entire clue.

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(Other definitions for naiad that I've seen before include "Classic spirit" , "watery spirit" , "Nymph of lakes, springs and rivers" , "Spring nymph" , "divine female figure" .)

I've seen this clue in The Times.

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