The most common and most likely answer to this crossword clue is the 4 letter word CLOT
I've seen this crossword clue in Independent
C
L
O
T
More clues leading to the result CLOT
- Fool left in bed
- Charlie leaping initially into bed
- Fool left lying in bed
- Herbert Lom, endlessly in court
- Fool caught by destiny
- A fool caught by fate
- Lecturer in bed getting medical problem
- Idiot in dress — the fellow getting thrown out
- Person intellectually challenged adding large number to 100
- Fool cuts material short
Buddy explains!

The straight part
We know that "Herbert" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case herbert = clot.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 CLOT mean?
CLOT noun- A thrombus, solidified mass of blood.
- A solidified mass of any liquid.
- A silly person.
- To form a clot or mass.
- To cause to clot or form into a mass.