most intransigent

awkward bullheaded cantankerous contrary hang tough hard-line headstrong immovable incompliant incurable indocile indomitable insoluble locked in mulish obdurate obstinate pat pertinacious perverse pigheaded recalcitrant refractory resolute self-willed set in stone tenacious tough tough-nut unbending uncompromising uncooperative undisciplined ungovernable unmanageable unpliable unruly unyielding wayward wild willful

amenable easy facile manageable

adamant inflexible obstinate resolute stubborn

tenacious

flexible pliant soft submissive willing yielding