Dates are wrongly filled up (5)
I believe the answer is:
sated
'filled up' is the definition.
'sated' can be an answer for 'filled' ('sate' can be a synonym of 'fill'). I'm unsure of the 'up' bit.
'dates are wrongly' is the wordplay.
'are wrongly' indicates an anagram.
'dates' is an anagram of 'SATED'.
Can you help me to learn more?
(Other definitions for sated that I've seen before include "fully filled" , "given more than enough" , "fully indulged" , "Stuffed, having had a surfeit" , "Stuffed with dates" .)