Weird at all times, that is (5)
I believe the answer is:
eerie
'weird' is the definition.
(both can mean strange or unsettling)
'at all times that is' is the wordplay.
'at all times' becomes 'eer' (archaic or poetic word meaning ever or forever).
'that is' becomes 'ie' (abbreviation for id est, 'that is' in Latin).
'eer'+'ie'='EERIE'
(Other definitions for eerie that I've seen before include "Spooky, creepy" , "Sinister" , "Spectral" , "Spooky, macabre" , "Uncannily strange" .)