Uniform on officer is something new in Scotland (4)
I believe the answer is:
unco
'something new in scotland' is the definition.
I can't tell whether this defines the answer.
'uniform on officer' is the wordplay.
'uniform' becomes 'U' (phonetic alphabet: alpha, bravo, charlie etc.).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'officer' becomes 'NCO' (abbreviation for non-commissioned officer).
'u'+'nco'='UNCO'
'is' is the link.
Can you help me to learn more?
(Other definitions for unco that I've seen before include "Rare" , "Very; odd (Scottish)" , "Strange; very (Scots.)" , "Very; unusual (Scots)" , "Remarkable Scottish" .)