early 15c., frigidite, "coldness," from Old French frigidité (15c.), from Late Latin frigiditatem (nominative frigiditas) "the cold," from Latin frigidus "cold" (see frigid). In reference to sexual impotence, 1580s, originally of men; by 1903 of women.
"to frighten," Middle English, from Old English fyrhtan "to terrify, fill with fear," from the source of fright (n.). Old English had also forhtian "be afraid, become full of fear, tremble," but the primary sense of the verb in Middle English was "to make afraid."
1580s, from French frégate (1520s), from Italian fregata (Neapolitan fregate), which with many names for types of sea vessels is of unknown origin. It is common to the Mediterranean languages (Spanish, Portuguese, Catalan fragata). Originally a small, swift vessel; the word was applied to progressively larger types over the years.
[A] light nimble vessel built for speed; employed in particular for the gleaning of intelligence and the protection and assault of trade-routes. In battle the frigates took station on the disengaged side of the fleet, where they repeated signals, sped on messages, and succoured the distressed. [Sir Geoffrey Callender, "Sea Passages," 1943]
In the old sailing navy usually they carried guns on a raised quarter-deck and forecastle, hence frigate-built (1650s) of a vessel having the quarter-deck and forecastle raised above the main-deck.