Overburdened with grammatical term (4)
I believe the answer is:
verb
'grammatical term' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe there's an association between them I don't understand?
'overburdened with' is the wordplay.
'with' indicates the answer is hidden within the clue.
'VERB' is hidden in the letters of 'overburdened'.
Can you help me to learn more?
(Other definitions for verb that I've seen before include "The predicate of a sentence" , "love, for example" , "Word such as run, make, or do" , "'In grammar, it denotes action (4)'" , "Type of word indicating action" .)