Narrow one's eyes at square dancing unit (6)
I believe the answer is:
squint
'narrow one's eyes' is the definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?
'at square dancing unit' is the wordplay.
'at' is a charade indicator (letters next to each other).
'square' becomes 'sq' (abbreviation for square in postal addresses).
'dancing' indicates anagramming the letters.
'unit' with letters rearranged gives 'uint'.
'sq' put next to 'uint' is 'SQUINT'.
Can you help me to learn more?
(Other definitions for squint that I've seen before include "Peep" , "Look in a cross-eyed way" , "Partly close one's eyes" , "Quick look" , "Have a problem seeing" .)