Tell you just how old the fruit is (4)
I believe the answer is:
date
'tell' is the definition.
The definition and answer can be both related to thinking as well as being verbs in their base form.
Maybe you can see an association between them that I don't see?
'just how old the fruit is' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
The remaining letters 'dae' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'you' is the link.
Can you help me to learn more?
(Other definitions for date that I've seen before include "Time - fruit - girlfriend" , "Appointment - fruit of palm" , "Particular time when event happened" , "may be fruitful" , "Go out with" .)