refusing to give in

unyielding

(of the skin) made hard (by rough work etc)

cruel, insensitive

determined and stubborn when trying to solve or complete something

determined, persistent

that cannot be calmed or satisfied

merciless, cruel

that cannot be bent; refusing to change or be influenced

stubborn

the commonest metal (symbol Fe), used in manufacturing and building, an also forming an essential part of blood; a flat-bottomed implement heated and used for smoothing clothes etc

hard, tough; inflexible

an animal that is the young of a horse and a donkey; a slipper without a heel

stubborn

stubborn

pig-headed, stubborn

without pity (and determined)

cruel, merciless

very determined

determined, strong-willed

stiff; that cannot be bent; firm; strict; not changing

stiff, strict, severe

serious and strict; not kind; (of the weather, attacks of disease etc) strong, extreme; making great demands on skill, ability, patience etc

uncompromising, stern

firmly fixed; loyal

loyal, steady

not easily bent or changed in shape; hard to stir, work, move etc; formal, unfriendly; thoroughly; a dead body

hard, inflexible

(of a person) having a strong, determined will; difficult to deal

obstinate, unyielding

fastened, fixed, fitting or held closely; stretched fully; (especially in compounds) made so that something cannot get out or in; packed so as to occupy the smallest possible space or to get in as much as possible

close, snug

not prepared to make any compromise

stubborn

complete; absolute

absolute, pure

not becoming less in force, degree

merciless

not willing to be with others

unfriendly

(especially of aims, purposes) not changing

straight