Expert leaves saying part of speech (4)
I believe the answer is:
verb
'part of speech' is the definition.
(verb is a kind of part of speech)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for verb that I've seen before include "Maybe protest" , "Word such as run, make, or do" , "love, for example" , "Type of word indicating action" , "Predicate of a sentance (4)" .)