Figure Diane a bit uptight (5)
I believe the answer is:
digit
'figure' is the definition.
(I've seen this before)
'diane a bit uptight' is the wordplay.
I cannot really see how this works, but
'diane' could be 'di' (I've seen this in other clues) and 'di' is located in the answer.
The remaining letters 'git' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for digit that I've seen before include "Finger; numeral" , "Need a bit of a hand" , "Single figure - finger" , "Finger; number" , "Finger, thumb or toe" .)