Quiver or quake (7)
I believe the answer is:
tremble
I believe this clue is a double definition.
'quiver' is the first definition.
(I've seen this in another clue)
'quake' is the second definition.
(synonyms)
(Other definitions for tremble that I've seen before include "quail" , "Shake with fear or excitement" , "Shake with fright or cold" , "Shiver slightly as with cold" , "Show fear" .)