intransitive. To continue firmly or obstinately in a state, opinion, purpose, or course of action, esp. despite opposition, setback, or failure…

intransitive. to stand in it: to remain steadfast or obstinate, to persevere or persist in one's course of action, belief, etc.; esp. (with clause…

Phrase. to make it tough. To be persistent or obstinate. Obsolete.

intransitive. To become or remain obdurate; to harden.

intransitive. To persist obstinately in an opinion, or a course of action; to insist.

to ride rusty: (of a person) to be obstinate or awkward; to be angry; to take offence; (of a horse) to be stubborn or difficult to control. Now rare.

To cause to penetrate, to drive in deeply. (Cf. 8) Colloquial phrase to dig in one's feet, to dig in one's heels, to dig in one's toes: to adopt…