Crossword Genius

He's ratty when interrupted by a teetotaller (3)

Ross

I believe the answer is:

ray

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'he's' is the definition.

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(Other definitions for ray that I've seen before include "may be electric" , "Man who engaged in surrealist photography" , "Second note for the flat fish" , "Beam; flat-bodied fish" , "Shaft, beam" .)

I've seen this clue in the Evening Standard.
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