A figure of speech to hamper translation (8)
I believe the answer is:
metaphor
'a figure of speech' is the definition.
(metaphor is a kind of figure of speech)
'to hamper translation' is the wordplay.
'translation' indicates an anagram.
'to'+'hamper'='tohamper'
'tohamper' anagrammed gives 'METAPHOR'.
(Other definitions for metaphor that I've seen before include "Figure of speech - allegory" , "7/16 [FIGURE OF SPEECH]" , "Captain of industry, eg" , "Allegorical figure" , "Expression where something is described as if it really is what it merely resembles" .)