Smiled when the spider got me agitated (8)
I believe the answer is:
simpered
'smiled' is the definition.
(simpering is a kind of smiling)
'the spider got me agitated' is the wordplay.
'got' means one lot of letters go next to another.
'agitated' is an anagram indicator.
'spider'+'me'='spiderme'
'spiderme' with letters rearranged gives 'SIMPERED'.
'when' acts as a link.
(Other definitions for simpered that I've seen before include "Smiled stupidly" , "Smiled in affected way" , "made with mince" .)