Support most of the ones like Tusk? (5)
I believe the answer is:
teeth
'ones like tusk?' is the definition.
'support most of the' is the wordplay.
'support' becomes 'tee' (tee is a kind of support).
'most of' means to remove the last letter.
'the' with its last letter taken off is 'th'.
'tee'+'th'='TEETH'
(Other definitions for teeth that I've seen before include "The most violent" , "Incisors maybe" , "Feature of an effective bill" , "Gearwheel cogs" , "Gearwheel projections" .)