God with new thing that's sharp (5)
I believe the answer is:
thorn
'that's sharp' is the definition.
(sharp part of a plant)
'god with new' is the wordplay.
'god' becomes 'thor' (Thor is an example).
'with' is a charade indicator (letters next to each other).
'new' becomes 'n' (abbreviation as in New Testament NT).
'thor'+'n'='THORN'
'thing' is the link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for thorn that I've seen before include "Sharp-pointed stem-tip" , "Something 20 [SHARP]" , "Cause of grief" , "Pointed extension of leaf" , "eg Prickle on rose" .)