Risk tip on needle (8)
I believe the answer is:
endanger
'risk' is the definition.
(to risk is to put in danger)
'tip on needle' is the wordplay.
'tip' becomes 'end'.
'on' means one lot of letters go next to another.
'needle' becomes 'anger'.
'end'+'anger'='ENDANGER'
(Other definitions for endanger that I've seen before include "Put in harm's way" , "Put someone at risk" , "compromise" , "Imperil" , "Threaten" .)