Walk on edges of narrowest grating (8)
I believe the answer is:
strident
'grating' is the definition.
(thesaurus)
'walk on edges of narrowest' is the wordplay.
'walk' becomes 'stride' (striding is a kind of walking**).
'on' means one lot of letters go next to another.
'edges of' says to hollow out the word (remove centre letters).
'narrowest' with its middle removed is 'nt'.
'stride'+'nt'='STRIDENT'
(Other definitions for strident that I've seen before include "harsh noise" , "Loud and harsh over tridents" , "Noisy" , "Harsh, grating" , "Commanding attention" .)