Try nut and bolt to secure area (9)
I believe the answer is:
endeavour
'try' is the definition.
(endeavouring is a kind of trying)
'nut and bolt to secure area' is the wordplay.
'nut' becomes 'en' ('nut' is printers' slang for an en space).
'and' is a charade indicator (letters next to each other).
'bolt' becomes 'devour'.
'to secure' means one lot of letters goes inside another.
'area' becomes 'a' (maths abbreviation).
'devour' placed around 'a' is 'deavour'.
'en'+'deavour'='ENDEAVOUR'
(Other definitions for endeavour that I've seen before include "Enterprise; earnest effort" , "Undertaking" , "Cook's old vessel" , "Try to achieve something" , "Try - Captain Cook's vessel" .)