"morbid fear of everything," attested by 1848 in medical journals for a psychological condition described as "monomania, with fear and terror," from Greek pantos, neuter genitive of pas "all" (see pan-) + -phobia. Earlier (by 1819) it was noted as an old word for "hydrophobia, rabies." Related: Pantophobe; pantophobic.
early 15c., from Old French temoros (14c.), from Medieval Latin timorosus "fearful," from Latin timor "fear, dread, apprehension, anxiety; religious awe, reverence," from timere "to fear, be afraid, dread," of unknown origin. Some early senses in English seem to show confusion with Middle English temerous "rash" (see temerity). Related: Timorously; timorousness.
"causing or attended by great fear, dreadful, awful," 1560s, from Latin dirus "fearful, awful, boding ill," a religious term, which is of unknown origin. Apparently a dialect word in Latin; perhaps from Oscan and Umbrian and perhaps cognate with Greek deinos "terrible," Sanskrit dvis- 'hate, enmity, enemy," from PIE root *dwei-, forming words for "fear; hatred."
1520s, "something that frightens, a scarecrow;" 1540s, "sudden panic, sudden terror inspired by a trifling cause, false alarm," from scare (v.). The earlier form was Middle English sker "fear, dread, terror, fright" (c. 1400). Scare tactic "attempt to manipulate public opinion by exploitation of fear" is by 1948.