One-piece garment not new in Friendly Islands (4)

I believe the answer is:

toga

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

'garment not new in friendly islands' is the definition.
'toga' can be an answer for 'garment' (I've seen this before). I am not sure about the 'not new in friendly islands' bit.

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for toga that I've seen before include "Roman male garb" , "Robe worn by Caesar" , "garment of old" , "Ancient Roman garment" , "Roman raiment" .)

I've seen this clue in The Times.

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