strong-minded 
adjective
Not easily influenced by others; resolute and determined: a strong-minded, independent woman...
- The influence of his strong-minded mother, who died when he was only 9, always remained with him.
- On the contrary, Berlinger is spiky and strong-minded, the archetypal independent filmmaker.
- The director of the local paper factory, an independent and strong-minded man, stood with the presidium.
Synonyms
determined, firm, resolute, resolved, purposeful, purposive, sure, self-disciplined, strong-willed, uncompromising, unyielding, unbending, unwavering, unswerving, unfaltering, unshakeable, inexorable, forceful, persistent, persevering, tenacious, dogged, stubborn;
dedicated, committed, stalwart;
North American rock-ribbed
informal gutsy, spunky
rare perseverant, indurate
Derivatives
strong-mindedness
- Just as his light verse is based on strong-mindedness, so his kindness was based on courage.
- Lucy's feminist strong-mindedness, in addition to her grace at the tea table, is in fact to her credit.
- To deprive your country of a batsman of epic strong-mindedness for the sake of a big gesture would not be appropriate to Hussain's career.