Garment covering one that's more nervous (7)
I believe the answer is:
jumpier
'more nervous' is the definition.
('jumpy' can be a synonym of 'nervous')
'garment covering one' is the wordplay.
I cannot quite see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'garment' could be 'jumper' (jumper is a kind of garment) and 'jumper' is found within the remaining letters.
No letters remain.
This explanation may well be incorrect...
'that's' is the link.
Can you help me to learn more?
(Another definition for jumpier that I've seen is " more nervous".)