The most common and most likely answer to this crossword clue is the 6 letter word QUIVER
I've seen this crossword clue in The Guardian
Q
U
I
V
E
R
More clues leading to the result QUIVER
Buddy explains!
The straight part
We know that "Tremble" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tremble = quiver.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 QUIVER mean?
QUIVER noun- A container for arrows, crossbow bolts or darts, such as those fired from a bow, crossbow or blowgun.
- A ready storage location for figurative tools or weapons.
- The collective noun for cobras.
- A multidigraph.
- Nimble, active.
- To shake or move with slight and tremulous motion; to tremble; to quake; to shudder; to shiver.