That will depend how you use the word.
He maintained his innocence. Synonyms could be claim, insist, and declare.
I maintain my mother's apartment. Synonyms could be look after, take care of, support.
The police maintain the peace in our neighborhood.Synonyms could be preserve, uphold, continue.
A synonym for "uphold" is "maintain" or "support."
inherit
I am only knowing one, a synonym for maintain is preserve.
aid help maintain
Maintain is a synonym for sustainable.
what is the best synonym for autocrat
The best synonym for emit is release.
hold, maintain, remain, withstand
Sprout is a good synonym.
The best synonym for vacuous is 'intelligent'
Best synonym for bossy is KING.
Synonym for respite: rest