digraph used in Old French for the "tsh" sound. In some French dialects, including that of Paris (but not that of Picardy), Latin ca- became French "tsha." This was introduced to English after the Norman Conquest, in words borrowed from Old French such as chaste, charity, chief (adj.). Under French influence, -ch- also was inserted into Anglo-Saxon words that had the same sound (such as bleach, chest, church) which in Old English still was written with a simple -c-, and into those that had formerly been spelled with a -c- and pronounced "k" such as chin and much.
It turns up as well in words from classical languages (chaos, echo, etc.). Most uses of -ch- in Roman Latin were in words from Greek, which in Greek would be pronounced correctly as /k/ + /h/, as in modern blockhead, but most Romans would have said merely /k/, and this was the regular pronunciation in English. Before c. 1500 such words were regularly spelled with a -c- (Crist, cronicle, scoole), but Modern English has preserved or restored the etymological spelling in most of them (chemical, chorus, monarch).
Sometimes ch- is written to keep -c- hard before a front vowel, as still in modern Italian. In some languages (Welsh, Spanish, Czech) ch- can be treated as a separate letter and words in it are alphabetized after -c- (or, in Czech and Slovak, after -h-). The sound also is heard in words from more distant languages (as in cheetah, chintz), and the digraph also is used to represent the sound in Scottish loch.
late Old English prud, prute "excellent, splendid; arrogant, haughty, having or cherishing a high opinion of one's own merits; guilty of the sin of Pride," from Old French prud, oblique case of adjective prouz "brave, valiant" (11c., Modern French preux; compare prud'homme "brave man"), from Late Latin prode "advantageous, profitable" (source also of Italian prode "valiant"), a back-formation from Latin prodesse "be useful."
This is a compound of pro- "before, for, instead of" (from PIE root *per- (1) "forward," hence "in front of, before, first, chief") + esse "to be" (from PIE root *es- "to be"). Also see pride (n.), prowess. "The -d- in prodesse is probably due to the influence of forms like red-eo-, 'I go back,' red-imo- 'I buy back,' etc." [OED]. The Old English form with -te probably is from or influenced by pride (Old English pryto).
Meaning "elated by some act, fact, or thing" is from mid-13c. The sense of "of fearless or untamable spirit" is by c. 1400; that of "ostentatious, grand, giving reason for pride" is by mid-14c. To do (someone) proud is attested by 1819. The surname Proudfoot is attested from c. 1200 (Prudfot). A Middle English term for "drunk and belligerent" was pitcher-proud (early 15c.).
The sense of "having a high opinion of oneself," not found in Old French, might reflect the Anglo-Saxons' opinion of the Norman knights who called themselves "proud." Old Norse pruðr, either from the same French source or borrowed from Old English, had only the sense "brave, gallant, magnificent, stately" (compare Icelandic pruður, Middle Swedish prudh, Middle Danish prud).
Likewise a group of "pride" words in the Romance languages — such as French orgueil, Italian orgoglio, Spanish orgullo — are borrowings from Germanic, where they had positive senses (Old High German urgol "distinguished").
Most Indo-European languages use the same word for "proud" in its good and bad senses, but in many the bad sense seems to be the earlier one. The usual way to form the word is by some compound of terms for "over" or "high" and words for "heart," "mood," "thought," or "appearance;" such as Greek hyperephanos, literally "over-appearing;" Gothic hauhþuhts, literally "high-conscience." Old English had ofermodig "over-moody" ("mood" in Anglo-Saxon was a much more potent word than presently) and heahheort "high-heart."
Words for "proud" in other Indo-European languages sometimes reflect a physical sense of being swollen or puffed up; such as Welsh balch, probably from a root meaning "to swell," and Modern Greek kamari, from ancient Greek kamarou "furnish with a vault or arched cover," with a sense evolution via "make an arch," to "puff out the chest," to "be puffed up" (compare English slang chesty).