The most common and most likely answer to this crossword clue is the 4 letter word PLOP
P
L
O
P
Buddy explains!
The straight part
We know that "a drop in the ocean" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a drop in the ocean = plop.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PLOP mean?
PLOP noun- A sound or action like liquid hitting a hard surface, or an object falling into a body of water.
- Excrement; derived from the "plop" sound made when it hits water in a toilet.
- To make the sound of an object dropping into a body of liquid.
- To land heavily or loosely.
- To defecate; derived from the "plop" sound made when excrement hits water in a toilet.