Girl almost taken in by trivial prediction (9)
I believe the answer is:
palmistry
'prediction' is the definition.
(palmistry is a kind of prediction)
'girl almost taken in by trivial' is the wordplay.
'girl' becomes 'miss' (synonyms).
'almost' means to remove the last letter (most of the word but not all of it).
'taken in by' means one lot of letters goes inside another.
'trivial' becomes 'paltry' (I've seen this before).
'miss' with its last letter taken off is 'mis'.
'mis' inserted within 'paltry' is 'PALMISTRY'.
(Other definitions for palmistry that I've seen before include "Hand reading" , "way to see ahead" , "Kind of fortune-telling" , "reading between the lines?" , "Telling the future by examining hand" .)