The phrase "spit in sea" is often used to describe something insignificant or inconsequential. It can also refer to an action that is pointless or futile. Other synonyms for this phrase include "a drop in the ocean," "a grain of sand," "a drop in the bucket," and "a needle in a haystack." All of these expressions convey the idea that something is so small or insignificant that it hardly makes a difference. While these phrases can be used to describe a variety of situations, they are most often used to express a sense of futility or disappointment in an outcome.