Slip of a girl, unusually shy, holds a record (5)
I believe the answer is:
sylph
'slip of a girl' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'unusually shy holds a record' is the wordplay.
'unusually' is an anagram indicator.
'holds' means one lot of letters goes inside another.
'a record' becomes 'L-P' (abbreviation for long play record).
'shy' is an anagram of 'syh'.
'syh' placed around 'lp' is 'SYLPH'.
Can you help me to learn more?
(Other definitions for sylph that I've seen before include "Slender, graceful girl" , "Slim female" , "Girl with slender figure" , "Imaginary spirit of the air" , "Graceful lass" .)