Having nap before four makes egghead tense and impatient (7)
I believe the answer is:
restive
'impatient' is the definition.
(I've seen this before)
'having nap before four makes egghead tense' is the wordplay.
I cannot quite see how this works, but
'nap' could be 'rest' (I've seen this in another clue) and 'rest' is found in the answer.
'four' could be 'iv' (Roman numerals for four) and 'iv' is located in the answer.
'egghead' could be 'e' (head letter of 'egg') and 'e' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'and' is the link.
Can you help me to learn more?
(Other definitions for restive that I've seen before include "Impatient - jumpy" , "It veers around, resisting control" , "Impatient of authority" , "Fidgety, uneasy" , "Uneasy, nervous" .)