First two characters on trail reported missing (6)
I believe the answer is:
absent
'missing' is the definition.
(similar in meaning)
'first two characters on trail reported' is the wordplay.
'first two characters' becomes 'ab' (A and B are the first letters of the alphabet).
'on' says to put letters next to each other.
'trail' becomes 'scent' (I've seen this before).
'reported' shows a homophone (sound like).
'scent' is a homophone of 'sent'.
'ab'+'sent'='ABSENT'
(Other definitions for absent that I've seen before include "AWOL" , "Not present - vacuous" , "Not at a specified place" , "Away" , "Not present or focused" .)