Shaking a container of missiles (7)
I believe the answer is:
aquiver
'shaking' is the definition.
(I've seen this before)
'a container of missiles' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
'container' could be 'quiver' (quiver is a kind of container) and 'quiver' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for aquiver that I've seen before include "Trembling" , "far from steady" , "shuddering" , "Flickering" , "shaking" .)