Head off disaster and have a party with fruit (7)
I believe the answer is:
avocado
'fruit' is the definition.
(I know that avocado is a type of fruit)
'head off disaster and have a party' is the wordplay.
'head off' means to remove the first letter.
'disaster' becomes 'havoc' (I've seen this before).
'and' says to put letters next to each other.
'have a party' becomes 'ado' (I am not sure about this - if you are sure you should believe this answer much more).
'havoc' with its first letter taken off is 'avoc'.
'avoc'+'ado'='AVOCADO'
'with' is the link.
Can you help me to learn more?
(Other definitions for avocado that I've seen before include "Dark green fruit like posh pear" , "Heavily stoned fruit" , "A fruit; a dull green" , "Savoury pear-shaped fruit" , "Large-stoned pear-shaped fruit" .)