"action of inspiring with awe," 1650s, verbal noun from awe (v.).

Middle English eilen, ailen, "trouble, afflict, harm," from Old English eglan "to trouble, plague, afflict," from Proto-Germanic *azljaz (source also of Old English egle "hideous, loathsome, troublesome, painful;" Gothic agls "shameful, disgraceful," agliþa "distress, affliction, hardship," us-agljan "to oppress, afflict"), from PIE *agh-lo-, suffixed form of root *agh- (1) "to be depressed, be afraid." Related: Ailed; ailing; ails.

From late Old English also of mental states and moods. Phrase what ails you? "what is wrong with you? why do you behave that way?" is by c. 1300 (what eileth the?)

It is remarkable, that this word is never used but with some indefinite term, or the word no thing; as What ails him? ... Thus we never say, a fever ails him. [Johnson]

Middle English aken, from Old English acan "suffer continued pain," from Proto-Germanic *akanan, which is perhaps from a PIE root *ag-es- "fault, guilt," with apparent cognates in Sanskrit and Greek, which itself is perhaps imitative of groaning.

Originally the verb was pronounced "ake," the noun "ache" (as in speak/speech). The noun changed its pronunciation to conform to the verb, but the spelling of both was changed to ache c. 1700 on a false assumption of a Greek origin (specifically Greek akhos "pain, distress," which rather is a distant relation of awe (n.)). Related: Ached; aching.

Greek hero of the Trojan War stories, bravest, swiftest, and handsomest of Agamemnon's army before Troy, he was son of Thetis and Peleus. His name is perhaps a compound of akhos "pain, grief" (see awe) + laos "the people, a people" (see lay (adj.)); or else it is from Pre-Greek (non-IE). Related: Achillean.

1590s, "profoundly reverential," from awe (n.) + -some (1). The meaning "inspiring awe or dread" is from 1670s; the weakened colloquial sense of "impressive, very good" is recorded by 1961 and was in vogue after c. 1980. Related: Awesomely; awesomeness.

also awestruck, "overwhelmed by reverential fear," 1630s (Milton), from awe (n.) + struck (see strike (v.)). Perhaps coined to cut a path between the contemporary senses of awesome ("reverential") and awful ("causing dread"). Awe-strike (v.) is not recorded until much later (1832), has always been rare, and is perhaps a back-formation.

c. 1300, agheful, aueful, "worthy of respect or fear, striking with awe; causing dread," from aghe, an earlier form of awe (n.), + -ful. The Old English word was egefull. The weakened sense of "very bad" is by 1809; the weakened sense of "excessively; very great" is by 1818. It formerly also was occasionally used in a sense of "profoundly reverential, full of awe" (1590s).

"subdue or control by fear or superior influence," 1570s, from over- + awe (v.). Perhaps coined by Spenser. Related: Overawed; overawing.