Man in middle of room keeping dry (4)
I believe the answer is:
otto
'man' is the definition.
(I have seen 'A man' mean 'otto' so perhaps 'man' could also mean 'otto')
'middle of room keeping dry' is the wordplay.
'middle of' means to look at the middle letters.
'keeping' is an insertion indicator.
'dry' becomes 'tt' (abbreviation for teetotal).
The middle letters of 'room' are 'oo'.
'oo' enclosing 'tt' is 'OTTO'.
'in' acts as a link.
(Other definitions for otto that I've seen before include "Italian for eight" , "Palindromic man's name" , "He's a German, whichever way you look at it" , "Ger. name (palindrome)" , "- Preminger, Austrian-born US film producer" .)