Someone who is pertinacious continues trying to do something difficult rather than giving up quickly.
英汉词典释义
adj.
坚持的;固执的;坚决的
a pertinacious illness痼疾pertinacious bigotry固执的偏见
英英词典释义
Adjective
1. stubbornly unyielding;
"dogged persistence""dour determination""the most vocal and pertinacious of all the critics""a mind not gifted to discover truth but tenacious to hold it"- T.S.Eliot"men tenacious of opinion"