Word before "lion" or "serpent" (3)
I believe the answer is:
sea
'word before lion or serpent' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sea that I've seen before include "Vast expanse" , "host of 1d [ADVENTURE]" , "Cause of flooding" , "7 [ship] s on this" , "70% of the earth's surface" .)