"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"
"men tenacious of opinion"

"a dour, self-sacrificing life"
"a forbidding scowl"
"a grim man loving duty more than humanity"
"undoubtedly the grimmest part of him was his iron claw"

"a dark scowl"
"the proverbially dour New England Puritan"
"a glum, hopeless shrug"
"he sat in moody silence"
"a morose and unsociable manner"
"a saturnine, almost misanthropic young genius"
"a sour temper"
"a sullen crowd"