The most common and most likely answer to this crossword clue is the 10 letter word CONSISTENT
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More clues leading to the result CONSISTENT
- Happy sister carried uniform
- Sibling wears comfortable uniform
- Steady relative in happy surroundings
- Little girl that’s happy to go round in uniform
- Happy to admit son is in agreement
- Pleased about half-sister being true to priniciples
- Happy to accept son is dependable
- Kid is to return medical device that’s fixed
- Sibling in comfortable uniform
- Harmonious and happy old Bob is kept inside
Buddy explains!

The straight part
We know that "that’s fixed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that’s fixed = consistent.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 CONSISTENT mean?
CONSISTENT noun- (in the plural) Objects or facts that are coexistent, or in agreement with one another.
- A kind of penitent who was allowed to assist at prayers, but was not permitted to receive the holy sacraments.
- Of a regularly occurring, dependable nature.
- Compatible, accordant.
- Of a set of statements: such that no contradiction logically follows from them.