Synonyms of 'unchanged'
For many years prices have remained virtually unchanged.
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The temperature should be kept more or less constant.
If you say that someone has fixed ideas or opinions, you mean that they do not often change their ideas and opinions, although perhaps they should.
people who have fixed ideas about things
Thesaurus for unchanged from the Collins English Thesaurus
If something is unchanged , it has stayed the same for a particular period of time.