The most common and most likely answer to this crossword clue is the 7 letter word MUTABLE
I've seen this crossword clue in The Times
M
U
T
A
B
L
E
More clues leading to the result MUTABLE
- Unsteady creature holding another up
- I’m not sure about diners possibly changing
- Bill invested in footwear that’s tending to change
- Cross nurses flap, being volatile
- Shifting item of furniture? There’s hesitation to climb at first
- Jenny adopted Bill
- Greek character with furniture that can change shape
- Stubborn sort pocketed bill, tending to change
Buddy explains!

The straight part
We know that "Unsteady" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unsteady = mutable.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 MUTABLE mean?
MUTABLE noun- Something mutable; a variable or value that can change.
- Changeable, dynamic, evolutive; inclined to change, evolve, mutate.
- (of a variable) Having a value that is changeable during program execution.