Maybe camping outside Dover, wanting nothing accidental (11)
I believe the answer is:
inadvertent
'accidental' is the definition.
(synonyms)
'maybe camping outside dover wanting nothing' is the wordplay.
'maybe camping' becomes 'in a tent' (camping is using a tent as shelter).
'outside' is an insertion indicator.
'wanting' suggests deleting specific letters (to want something can mean to lack it or need it).
'nothing' becomes 'O' (O resembles 0).
'dover' with 'o' removed is 'dver'.
'inatent' enclosing 'dver' is 'INADVERTENT'.
(Other definitions for inadvertent that I've seen before include "without meaning" , "Unthinking" , "Accidental" , "Unintentional" , "Careless" .)