Pleasant exercises with a climber (5,3)
I believe the answer is:
sweet pea
'climber' is the definition.
(I know that sweet pea is a type of vine)
'pleasant exercises with a' is the wordplay.
'pleasant' becomes 'sweet' (I've seen this in another clue).
'exercises' becomes 'pe' (Physical Education class).
'with' means one lot of letters go next to another.
'sweet'+'pe'+'a'='SWEET PEA'
(Other definitions for sweet pea that I've seen before include "Pew tease (anag) - flower" , "Climbing garden plant with pastel flowers" , "Highly-scented garden climber" , "bloomer" , "A wee pest on fragrant climbing plant" .)