Fountain: in it tossed up clergyman (5)
I believe the answer is:
trevi
'fountain' is the definition.
(I've seen this before)
'in it tossed up clergyman' is the wordplay.
'in' means one lot of letters goes inside another.
'tossed up' is an anagram indicator.
'clergyman' becomes 'rev' (I've seen this before).
'it' is an anagram of 'ti'.
'ti' going around 'rev' is 'TREVI'.
(Other definitions for trevi that I've seen before include "Roman fountain" , "Rome fountain" , "flowing in Rome" .)