Tremble, seeing case for arrows (6)
I believe the answer is:
quiver
This clue is a double definition.
'tremble' is the first definition.
(quivering is a kind of trembling)
'case for arrows' is the second definition.
(I've seen this before)
'seeing' is the link.
(Other definitions for quiver that I've seen before include "Wobble" , "Tremble - case for arrows" , "Receptacle in which archer keeps arrows" , "Arrow case" , "Tremble and shake, or receptacle for arrows" .)