Old shrub left by yard (7)
I believe the answer is:
elderly
'old' is the definition.
('elderly' can be similar in meaning to 'old')
'shrub left by yard' is the wordplay.
'shrub' becomes 'elder' (elder is a kind of shrub**).
'left' becomes 'l' (common abbreviation).
'by' means one lot of letters go next to another.
'yard' becomes 'y'.
'elder'+'l'+'y'='ELDERLY'
(Other definitions for elderly that I've seen before include "Not young" , "Fairly old, past middle age" , "... or not of tender years" , "Getting on in years" , "Quite old" .)