adamant, adamantine, dogged, hard, hardened, hardheaded, headstrong, immovable, implacable, inflexible, mulish, obdurate, persistent, pertinacious, perverse, pigheaded, rigid, self-willed, stubborn, tenacious, unbending, uncompromising, unrelenting, unyielding, willful (or wilful);
on one's mettle;
SINGLE-MINDED Defined for English Language Learners
Definition of single-minded for English Language Learners
: having only one purpose, goal, or interest : focused on one thing
Seen and Heard
What made you want to look up single-minded? Please tell us where you read or heard it (including the quote, if possible).