(said of the state of the mind) not changing, fickle or wavering.

a man not affected by external happenings as gain, loss, fear, joy, distress, disappointment, etc.; a steadfast man.

the quality of a person who is unaffected external happenings as gain, loss, fear, joy, distress, disappointment, etc.; steadfastness of the mind.

a woman of this nature; a steadfast-woman.