Cartoon pint drawn by a gadget (11)
I believe the answer is:
contraption
'a gadget' is the definition.
(synonyms)
'cartoon pint drawn' is the wordplay.
'drawn' indicates anagramming the letters (the letters drawn up in a different way).
'cartoon'+'pint'='cartoonpint'
'cartoonpint' is an anagram of 'CONTRAPTION'.
'by' is the link.
(Other definitions for contraption that I've seen before include "Strange machine" , "device" , "Appliance" .)