Russian's a little vigorous (4)

I believe the answer is:

igor

'russian's' is the definition.
(I've seen this before)

'a little vigorous' is the wordplay.
'a little' indicates the answer is hidden within the clue.
'IGOR' is hidden within 'vigorous'.

(Other definitions for igor that I've seen before include "Prince of grand opera" , "Hero of Borodin" , "Russian man" , "Prince of Russian opera" , "Maybe 8 [SIKORSKY]" .)

I've seen this clue in The Everyman puzzle in The Observer.

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