Origin and history of diligence

late Old English, "benevolence for the poor," also "Christian love in its highest manifestation," from Old French charité "(Christian) charity, mercy, compassion; alms; charitable foundation" (12c.), from Latin caritatem (nominative caritas) "costliness; esteem, affection," from carus "dear, valued" (from PIE *karo-, from root *ka- "to like, desire").

In the Vulgate the Latin word often is used as translation of Greek agape "love" — especially Christian love of fellow man — perhaps to avoid the sexual suggestion of Latin amor). The Vulgate also sometimes translated agape by Latin dilectio, noun of action from diligere "to esteem highly, to love" (see diligence).

Wyclif and the Rhemish version regularly rendered the Vulgate dilectio by 'love,' caritas by 'charity.' But the 16th c. Eng. versions from Tindale to 1611, while rendering agape sometimes 'love,' sometimes 'charity,' did not follow the dilectio and caritas of the Vulgate, but used 'love' more often (about 86 times), confining 'charity' to 26 passages in the Pauline and certain of the Catholic Epistles (not in I John), and the Apocalypse .... In the Revised Version 1881, 'love' has been substituted in all these instances, so that it now stands as the uniform rendering of agape. [OED]

The general sense of "affections people ought to feel for one another" is from c. 1300. Also from c. 1300 as "an act of kindness or philanthropy," also "alms, that which is bestowed gratuitously on a person or persons in need." The sense of "charitable foundation or institution" in English is attested by 1690s. The meaning "liberality in judging others or their actions" is from late 15c. A charity-school (1680s) educated (and sometimes housed and fed) poor children and was maintained by voluntary contributions or bequests.

"artificial penis used for female gratification," 1590s, a word of unknown origin. Traditional guesses include a corruption of Italian deletto "delight" (from Latin dilectio, noun of action from diligere "to esteem highly, to love;" see diligence) or a corruption of English diddle. None of these seems very convincing (Florio's dictionary glosses many words with dildo, but deletto is not one of them.) Century Dictionary perhaps gets closer to the mark:

A term of obscure cant or slang origin, used in old ballads and plays as a mere refrain or nonsense-word; also used, from its vagueness, as a substitute for various obscene terms and in various obscene meanings. [1895]

The earliest use of the word in this sense, and probably the start of its popularity, seems to be via Nashe:

"Curse Eunuke dilldo, senceless counterfet" ["Choise of Valentines or the Merie Ballad of Nash his Dildo," T. Nashe, c. 1593]

Other early forms include dildoides (1675), dildidoes (1607). Middle English had dillidoun (n.) "a darling, a pet" (mid-15c.), from Old Norse dilla "to lull" (hence dillindo "lullaby"). Dildin seems to be a term for "sweetheart" in a 1675 play:

Mir.: Here comes a lusty Wooer, my dildin, my darling.

Here comes a lusty Wooer Lady bright and shining.

The thing itself is older. They loom large in the Greek mimes (Herondas uses baubon). A classical Latin word for one was fascinum (see fascinate). In later English sometimes a French word, godemiché, was used (1879). Also used in 18c. of things that resemble dildoes, e.g. dildo pear (1756), dildo cactus (1792). 

Shakespeare plays on the double sense, sexual toy and ballad refrain, in "A Winter's Tale."

SERVANT: He hath songs for man or woman, of all sizes; no

milliner can so fit his customers with gloves: he

has the prettiest love-songs for maids; so without

bawdry, which is strange; with such delicate

burthens of dildos and fadings, 'jump her and thump

her;' and where some stretch-mouthed rascal would,

as it were, mean mischief and break a foul gap into

the matter, he makes the maid to answer 'Whoop, do me

no harm, good man;' puts him off, slights him, with

'Whoop, do me no harm, good man.'