The most common and most likely answer to this crossword clue is the 8 letter word METONYMS
I've seen this crossword clue in Financial Times
M
E
T
O
N
Y
M
S
Buddy explains!

The straight part
We know that "figures of speech" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case figures of speech = metonyms.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does METONYMS mean?
METONYMS noun- (grammar) A word that names an object from a single characteristic of it or of a closely related object; a word used in metonymy.
- (by extension) A concept, idea, or word used to represent, typify, or stand in for a broader set of ideas.