Awkward when trying to gain height thus? (7)

I believe the answer is:

stilted

'awkward' is the definition.
(thesaurus)

I don't understand how the rest of the clue works.

(Other definitions for stilted that I've seen before include "Bombastic (of speech, writing)" , "Unnatural sounding and overformal" , "Awkward" , "Stiff and unnatural" , "Stiff and pompous" .)

I've seen this clue in The Guardian.

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