adj. 25B6; adjective
a decisive man : RESOLUTE, firm, strong-minded, strong-willed, determined; purposeful, forceful, dead set, unwavering, unyielding, unbending, inflexible, unshakeable, obstinate, stubborn; N. Amer. rock-ribbed.
the decisive factor : DECIDING, conclusive, determining; key, pivotal, critical, crucial, significant, influential, major, chief, principal, prime.