Had left hand grenade around there to threaten them (8)
I believe the answer is:
endanger
'there to threaten them' is the definition.
I can't judge whether this defines the answer.
'had left hand grenade around' is the wordplay.
'left' indicates named letters should be taken away.
'around' indicates an anagram.
'hand'+'grenade'='handgrenade'
'handgrenade' with 'had' taken out is 'ngrenade'.
'ngrenade' is an anagram of 'ENDANGER'.
Can you help me to learn more?
(Other definitions for endanger that I've seen before include "To put one at risk" , "Put in jeopardy" , "Hazard" , "Put someone at risk" , "Put in harm's way" .)