unemotional

Not easily stirred or moved in feeling.

Involving little or no emotion; rational.

Not emotional; free from or unaccompanied by an exhibition of emotion or feeling; impassive; not inducing emotion: as, an unemotional person; an unemotional book.

Showing little or no feeling.

Reasoned and objective, involving reason or intellect rather than feelings.

unsusceptible to or destitute of or showing no emotion

cool and formal in manner