It's no small matter, say, translating TS Eliot (7)
I believe the answer is:
litotes
'it's no small matter' is the definition.
I can't tell whether this defines the answer.
'translating ts eliot' is the wordplay.
'translating' indicates an anagram.
'ts'+'eliot'='tseliot'
'tseliot' with letters rearranged gives 'LITOTES'.
'say' is the link.
Can you help me to learn more?
(Other definitions for litotes that I've seen before include "Understatement for rhetorical effect" , "Town of N. Norway" , "Ironic figure of speech" , "Literary use of understatement" , "in which not a little is a lot?" .)