Poison makes you move uneasily around mid-morning (5)
I believe the answer is:
venom
'poison' is the definition.
(I know that venom is a type of animal toxin)
'move uneasily around mid-morning' is the wordplay.
'uneasily' is an anagram indicator.
'around' means one lot of letters goes inside another.
'mid' says to take the centre (mid- can mean the middle of something).
The centre of 'morning' is 'n'.
'move' with letters rearranged gives 'veom'.
'veom' enclosing 'n' is 'VENOM'.
'makes you' is the link.
(Other definitions for venom that I've seen before include "ill will" , "essential part of The Sting" , "Poisonous liquid of snakes" , "Spite: toxin" , "Virulence" .)