"modest, bashful," 1550s, a folk-etymology alteration of shamefast, "modest, humble, virtuous," also "ashamed of one's behavior," from Old English scamfæst "bashful," literally "restrained by shame," or else "firm in modesty," from shame (n.) + -fæst, adjectival suffix (see fast (adj.)). Related: Shamefacedly; shamefacedness.
shamefaced, -fast. It is true that the second is the original form, that -faced is due to a mistake, & that the notion attached to the word is necessarily affected in some slight degree by the change. But those who, in the flush of this discovery, would revert to -fast in ordinary use are rightly rewarded with the name of pedants .... [Fowler]
updated on August 03, 2022