A diversion causing Tony to lose his way (3)
I believe the answer is:
toy
'a diversion' is the definition.
(I've seen this in another clue)
'tony to lose his way' is the wordplay.
I cannot quite see how this works, but
'to' is within the answer.
A single letter 'y' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'causing' is the link.
Can you help me to learn more?
(Other definitions for toy that I've seen before include "A child's plaything" , "Child's amusement" , "Teddy or Dolly" , "Trifle or dally with" , "One of spelt out words" .)