Prudish type at start of seasonal shoot (5)
I believe the answer is:
sprig
'shoot' is the definition.
(I've seen this in another clue)
'prudish type at start of seasonal' is the wordplay.
'prudish type' becomes 'prig' (I've seen this in another clue).
'at' means one lot of letters go next to another (I've seen this in other clues).
'start of' indicates taking the first letters.
The initial letter of 'seasonal' is 's'.
'prig' after 's' is 'SPRIG'.
(Other definitions for sprig that I've seen before include "Grips with a small branch" , "Small twig" , "Small leafy stem" , "Shoot - twig" , "Younger member of family" .)