Her uniform may be tiny (5)
I believe the answer is:
unity
'her' is the definition.
I can't tell whether this defines the answer.
'uniform may be tiny' is the wordplay.
'uniform' becomes 'U' (phonetic alphabet: alpha, bravo, charlie etc.).
'may be' is an anagram indicator.
'tiny' is an anagram of 'nity'.
'u'+'nity'='UNITY'
Can you help me to learn more?
(Other definitions for unity that I've seen before include "One - mutual agreement" , "Accord" , "Completeness (with nothing wanting)" , "State of being joined as a whole" , "Number one" .)