High street department stores vanished, first off (6)
I believe the answer is:
stoned
'high' is the definition.
(I've seen this before)
'street department stores vanished first off' is the wordplay.
'street' becomes 'st'.
'department' becomes 'd' (abbreviation eg in MOD Ministry of Defence).
'stores' is an insertion indicator.
'vanished' becomes 'gone' (going is a kind of vanishing).
'first off' means to remove the first letter.
'st'+'d'='std'
'gone' with its first letter taken off is 'one'.
'std' going around 'one' is 'STONED'.
(Other definitions for stoned that I've seen before include "with jewels" , "Under the influence of drugs (colloq.)" , "Doesn't (anag) - drunk" , "High on a drug" , "Stephen thus martyred" .)