Bound to be suffering a beastly impediment (7)
I believe the answer is:
hogtied
'suffering a beastly impediment' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs sometimes define each other.
'bound to be' is the wordplay.
'bound' becomes 'tied' (similar in meaning).
'to' means one lot of letters go next to another (I've seen this in other clues).
'be' becomes 'hog' (I can't justify this - if you can you should believe this answer much more).
'tied' put after 'hog' is 'HOGTIED'.
Can you help me to learn more?
(Another definition for hogtied that I've seen is " Members bound".)