Managed with one in shower (4)
I believe the answer is:
rain
'shower' is the definition.
(synonyms)
'managed with one' is the wordplay.
'managed' becomes 'ran' (I've seen this before).
'with' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'ran' enclosing 'i' is 'RAIN'.
'in' is the link.
(Other definitions for rain that I've seen before include "eg A shower" , "bad weather" , "The ---, it ---eth every day (T.Night)" , "See 12" , "Falling moisture" .)