Contradictory facial expression for one providing support (9)

I believe the answer is:

crossbeam

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'contradictory facial expression' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.

'one providing support' is the wordplay.
'one providing' becomes 'cross' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'support' becomes 'beam' (beam is a kind of support).
'cross'+'beam'='CROSSBEAM'

'for' acts as a link.

Can you help me to learn more?

(Another definition for crossbeam that I've seen is " Support".)

I've seen this clue in The Times.

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