An agitated Sioux with a worried look (7)

I believe the answer is:

anxious

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'worried look' is the definition.
'anxious' can be an answer for 'worried' (I've seen this before). I am unsure of the 'look' bit.

'an agitated sioux with a' is the wordplay.
'an agitated' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'a' becomes 'an'.
'sioux' anagrammed gives 'xious'.
'xious' put after 'an' is 'ANXIOUS'.

Can you help me to learn more?

(Other definitions for anxious that I've seen before include "Apprehensive, uneasy" , "Uneasy, worried" , "Restless" , "Nervy" , "On edge" .)

I've seen this clue in The Globe and Mail.

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