Unsuitable interest surrounds origins of environmental protesters (5)
I believe the answer is:
inept
'unsuitable' is the definition.
(I've seen this before)
'interest surrounds origins of environmental protesters' is the wordplay.
'interest' becomes 'int'.
'surrounds' means one lot of letters goes inside another.
'origins of' indicates taking the first letters.
The initial letters of 'environmental protesters' is 'ep'.
'int' going around 'ep' is 'INEPT'.
(Other definitions for inept that I've seen before include "Incompetent or awkward" , "Clumsy - silly" , "Foolish" , "Unskilful, awkward" , "Hopeless; bungling" .)