Reptile Elizabeth found beside a road (6)
I believe the answer is:
lizard
'reptile' is the definition.
(I know that lizard is a reptile)
'elizabeth found beside a road' is the wordplay.
'elizabeth' becomes 'liz' (short for Elizabeth).
'found' means one lot of letters go next to another.
'beside' is a charade indicator (letters next to each other).
'road' becomes 'rd' (abbreviation).
'liz'+'a'+'rd'='LIZARD'
(Other definitions for lizard that I've seen before include "Gecko, for example" , "See 1 Across" , "A reptile; a Cornish Head" , "Reptile such as skink" , "Reptile with two pairs of legs" .)