Having no part or share (in or of); not sharing or participating in; exempt, spared; deprived of. Obsolete.

Holding aloof. Obsolete.

Lacking affection or warmth of feeling, often in a manner suggesting a (disproportionate) sense of one's own superiority; cold, unfriendly…

Of a person: seemingly set apart or distant from others in manner; withdrawn, reserved; aloof. Also of a person's expression, manner, etc.

That does not participate or take part; = unparticipant, adj.

Not participant; that does not participate or take part. Hence: detached, uninvolved.

That does not participate; not taking part.

Of persons, their conduct, etc.: characterized by detachment (see detachment, n. 4b).