1 a (1) : unreasonably or perversely unyielding : mulish (2) : justifiably unyielding : resolute b : suggestive or typical of a strong stubborn nature a stubborn jaw 2 : performed or carried on in an unyielding, obstinate, or persistent manner stubborn effort 3 : difficult to handle, manage, or treat a stubborn cold 4 : lasting stubborn facts