“previous”

Coming before in time, order, or position.

“The preceding chapter laid the groundwork for the dramatic revelation.”

Best for: Clean and formal; works well in academic or structured writing.

Existing or occurring before something else in time or sequence.

“Her antecedent career in law gave her an edge in corporate negotiations.”

Best for: Strong in formal, legal, or philosophical contexts; carries intellectual weight.

Former or previous, especially referring to a past state or role.

“His erstwhile mentor had long since abandoned the principles he once preached.”

Best for: Best for describing people or relationships that have changed; slightly wistful tone.

Already mentioned or dealt with earlier in a sequence.

“The foregoing evidence makes any further argument difficult to sustain.”

Best for: Precise and legalistic; ideal in reports, contracts, or formal arguments.

Belonging to a period before a major event, often humorously implying extreme age.

“He clung to antediluvian methods that baffled his younger colleagues.”

Best for: Used for comic or dramatic effect; implies the past was almost absurdly long ago.

That once was; former or one-time.

“The quondam champion sat quietly in the back row, unrecognized.”

Best for: Rare and distinctly literary; best reserved for writing where obscurity adds elegance.