Girl round about inside far from reticent (5)
I believe the answer is:
vocal
'far from reticent' is the definition.
I can't judge whether this defines the answer.
'girl round about inside' is the wordplay.
'girl' becomes 'val' (short for Valerie).
'round' is an insertion indicator.
'about inside' becomes 'oc' (I can't justify this - if you can you should give a lot more credence to this answer).
'val' going around 'oc' is 'VOCAL'.
Can you help me to learn more?
(Other definitions for vocal that I've seen before include "With lots to say" , "Outspoken (e.g. criticism)" , "(Performance of) piece that is sung" , "not instrumental" , "Relating to the human voice" .)