Some lacking cover having trust as at outset new insurance arranged (9)
I believe the answer is:
naturists
'some lacking cover' is the definition.
(people lacking cover or clothing)
'trust as at outset new insurance arranged' is the wordplay.
'at outset' says to take the initial letters.
'arranged' indicates anagramming the letters.
The first letters of 'new insurance' is 'ni'.
'trust'+'as'+'ni'='trustasni'
'trustasni' with letters rearranged gives 'NATURISTS'.
'having' acts as a link.
(Other definitions for naturists that I've seen before include "Those going naked" , "Nudists" .)