Gardner pursuing good high-class fruit (5)
I believe the answer is:
guava
'fruit' is the definition.
(guava is a kind of fruit)
'gardner pursuing good high-class' is the wordplay.
'gardner' becomes 'ava' (Ava Gardner).
'pursuing' means one lot of letters go next to another.
'good' becomes 'g' (abbreviation).
'high class' becomes 'u'.
'g'+'u'='gu'
'ava' after 'gu' is 'GUAVA'.
(Other definitions for guava that I've seen before include "South American fruit" , "Tropical fruit with yellow skin and pink pulp" , "Pale orange tropical fruit" , "Leaving body" , "Tropical tree with yellow fruit" .)