steady has 18 distinct synonyms spread across 7 of its 10 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is unsteady.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
not subject to change or variation especially in behavior
“a steady beat”
marked by firm determination or resolution; not shakable
“firm convictions”
a person loved by another person
2 of the 10 recorded senses carry no synonym, antonym or related term, so they are not shown above. Every sense, with its definition and examples, is on the full entry for steady.
Synonyms, antonyms and the broader and narrower relations for steady come from Princeton University’s WordNet. Full sources and licences.