Frederick

"impressed with fear, fearful," early 14c., originally the past participle of the now-obsolete Middle English verb afray "frighten," from Anglo-French afrayer, Old French affrai, effrei, esfrei "disturbance, fright," from esfreer (v.) "to worry, concern, trouble, disturb," from Vulgar Latin *exfridare, a hybrid word meaning literally "to take out of peace."

The first element is from Latin ex "out of" (see ex-). The second is Frankish *frithu "peace," from Proto-Germanic *frithuz "peace, consideration, forbearance" (source also of Old Saxon frithu, Old English friu, Old High German fridu "peace, truce," German Freide "peace"), from a suffixed form of PIE root *pri- "to be friendly, to love."

A rare case of an English adjective that never stands before a noun. Because it was used in the King James Bible, it acquired independent standing and thrived while affray faded, and it chased off the once more common afeared. Colloquial sense in I'm afraid "I regret to say, I suspect" (without implication of fear, as a polite introduction to a correction, admission, etc.) is recorded by 1590s.

Her blue affrayed eyes wide open shone [Keats, "The Eve of St. Agnes," 1820]

sixth day of the week, Old English frigedæg "Friday, Frigga's day," from Frige, genitive of *Frigu (see Frigg), Germanic goddess of married love. The day name is a West Germanic translation of Latin dies Veneris "day of (the planet) Venus," which itself translated Greek Aphrodites hēmera.

Compare Old Norse frijadagr, Old Frisian frigendei, Middle Dutch vridach, Dutch vrijdag, German Freitag "Friday," and the Latin-derived cognates Old French vendresdi, French vendredi, Spanish viernes. In Germanic religion, Freya (q.v.) corresponds more closely in character to Venus than Frigg does, and some early Icelandic writers used Freyjudagr for "Friday."

A fast-day in the Church, hence Friday face (17c.) for a gloomy countenance.