unexcitable

Mr. Card was apparently the most stoical of men—of a clear, unexcitable temperament, with unorthodox and vague religious ideas.

He was ardently loyal, but an unexcitable, matter-of-fact sort of person.

A quiet, unexcitable mental characteristic is the utmost necessity.

Truly the scene was beautiful, and one to breathe a warlike spirit into the most unexcitable.