Strange - that's always in front! (5)
I believe the answer is:
eerie
'strange' is the definition.
(thesaurus)
'that's always in front' is the wordplay.
'that's' becomes 'ie'.
'always' becomes 'eer' (poetic way of saying ever).
'in front' means one lot of letters go next to another.
'ie' after 'eer' is 'EERIE'.
(Other definitions for eerie that I've seen before include "Weird, uncanny" , "Frighteningly odd" , "Spooky, creepy" , "Spooky, macabre" , "Spectral" .)