Downright see-through! (5)

I believe the answer is:

sheer

This clue is a double definition.

'downright' is the first definition.
(I know that downright can be written as sheer)

'see-through' is the second definition.
(synonyms)

(Other definitions for sheer that I've seen before include "Utter - precipitous" , "Film" , "needing to change a course" , "Deviate (from) - vertical" , "Downright - deviation" .)

I've seen this clue in the Evening Standard.

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