Bumped into Harpo transformed as a figure of speech (8)
I believe the answer is:
metaphor
'a figure of speech' is the definition.
(metaphor is a kind of figure of speech)
'bumped into harpo transformed' is the wordplay.
'bumped into' becomes 'met' (I've seen this before).
'transformed' indicates anagramming the letters.
'harpo' anagrammed gives 'aphor'.
'met'+'aphor'='METAPHOR'
'as' is the link.
(Other definitions for metaphor that I've seen before include "Analogy" , "A common fugure of speech" , "To hamper, badly, a figure of speech" , "Don't take that literally" , "Top harem is a figure of speech" .)