Underwater boats with bed and emergency room for member (10)
I believe the answer is:
subscriber
'member' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'underwater boats with bed and emergency room' is the wordplay.
'underwater boats' becomes 'subs' (I can't explain this - if you can you should believe this answer much more).
'with' means one lot of letters go next to another.
'bed' becomes 'crib' (bed for a child).
'and' means one lot of letters go next to another.
'emergency room' becomes 'ER' (abbreviation popularized by US TV series).
'subs'+'crib'+'er'='SUBSCRIBER'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for subscriber that I've seen before include "paid-up customer?" , "underwriter?" , "One showing approval of idea" , "One on the telephone" .)