The most common and most likely answer to this crossword clue is the 4 letter word GLUT
G
L
U
T
More clues leading to the result GLUT
- Flood is natural around lake
- Stomach accommodates large excess
- Large intestine absorbed excess
- Excess left in stomach
- Fifty caught in a bit of a fiddle
- Stomach consuming large surfeit
- What litres poured into stomach may constitute!
- Large in stomach from excess
- Line to enter attraction doubling back? Far too much
- Lots left in stomach
Buddy explains!

The straight part
We know that "Overstuff" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case overstuff = glut.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 GLUT mean?
GLUT noun- An excess, too much.
- That which is swallowed.
- Something that fills up an opening.
- A wooden wedge used in splitting blocks.
- A piece of wood used to fill up behind cribbing or tubbing.
- (bricklaying) A bat, or small piece of brick, used to fill out a course.
- An arched opening to the ashpit of a kiln.
- A block used for a fulcrum.
- The broad-nosed eel (Anguilla anguilla, syn. Anguilla latirostris), found in Europe, Asia, the West Indies, etc.
- To fill to capacity; to satisfy all demand or requirement; to sate.
- To eat gluttonously or to satiety.