Wearing nothing old, Lear's daughter leaves for season? (7)
I believe the answer is:
oregano
'leaves for season?' is the definition.
(leaves for seasoning)
'wearing nothing old lear's daughter' is the wordplay.
'wearing' is an insertion indicator.
'nothing' becomes 'O' (O resembles 0).
'old' becomes 'o' (abbreviation).
'lear's daughter' becomes 'Regan' (in Shakespeare's King Lear).
'o'+'o'='oo'
'oo' going around 'regan' is 'OREGANO'.
(Other definitions for oregano that I've seen before include "Dried marjoram" , "Herb - a no-goer (anag)" , "Gear Ono up for the herb" , "Herb used in cookery" , "Mediterranean herb" .)