Head honky came round with Leon the Lizard (9)
I believe the answer is:
chameleon
'lizard' is the definition.
(chameleon is a kind of lizard)
'head honky came round with leon' is the wordplay.
'head' says to take the initial letters.
'round with' is an anagram indicator.
The initial letter of 'honky' is 'h'.
'h'+'came'='hcame'
'hcame' anagrammed with 'leon' can make 'CHAMELEON'.
'the' is the link.
(Other definitions for chameleon that I've seen before include "Lizard that can change its colours" , "Animal that changes colour" , "blender" , "Variable-colour reptile" , "Someone who changes position to suit the situation" .)