The most common and most likely answer to this crossword clue is the 5 letter word SLUSH
S
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H
More clues leading to the result SLUSH
Buddy explains!

The straight part
We know that "drivel" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case drivel = slush.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 SLUSH mean?
SLUSH noun- Half-melted snow or ice.
- Liquid mud or mire.
- Flavored shaved ice served as a drink.
- A soft mixture of grease and other materials, used for lubrication.
- The refuse grease and fat collected in cooking, especially on shipboard.
- A mixture of white lead and lime, used as a paint to prevent oxidation.
- Unsolicited manuscripts, as in slush pile.
- To smear with slushy liquid or grease.
- To slosh or splash; to move as, or through, a slushy or liquid substance.
- To paint with a mixture of white lead and lime.