Fool roaming around with us (9)
I believe the answer is:
ignoramus
'fool' is the definition.
(I've seen this before)
'roaming around with us' is the wordplay.
'around with' indicates anagramming the letters.
'roaming' mixed up with 'us' can make 'IGNORAMUS'.
(Other definitions for ignoramus that I've seen before include "Uninformed sort" , "one in a state of bliss?" , "Stupid person" , "One is not intelligent" , "Ignorant person" .)