Tree arborist saws hibiscus tips (3)
I believe the answer is:
ash
'tree' is the definition.
(ash is a kind of tree)
'arborist saws hibiscus tips' is the wordplay.
'tips' says to take the initial letters (tip can refer to the top end of something).
The first letters of 'arborist saws hibiscus' is 'ASH'.
(Other definitions for ash that I've seen before include "Timber tree" , "In fireplace it may be" , "Volcanic dust" , "Tree; cinders" , "Oleaceous tree" .)