Girl almost taken in by trivial prediction (9)
I believe the answer is:
Here is my best explanation:
'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'.