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.
"deliberate erotic self-stimulation," 1711 (earlier as mastupration, 1620s), from French masturbation and directly from Modern Latin masturbationem (nominative masturbatio), noun of action from past-participle stem of Latin masturbari "to masturbate."
The long-standing speculation is that this Latin word is altered (probably by influence of turbare "to disturb, confuse") from *manstuprare, from manu, ablative of manus "hand" (see manual) + stuprare "defile" (oneself), from stuprum "defilement, dishonor," related to stupere "to be stunned, stupefied" (see stupid). Hence the earliest form of the word in English. But perhaps the first element represents an unattested *mazdo- "penis" [OED]. An earlier technical word for this was onanism. Related: Masturbational.
Farmer and Henley ["Slang and Its Analogues," 1898] lists among the slang terms for "to masturbate" or "masturbation" frig (which they trace to Latin fricare "to rub") to bob; to box the Jesuit; to chuff, to chuffer; to claw; to digitate (of women); to fight one's turkey (Texan); to handle; to indorse; to milk; to mount a corporal and four; to dash one's doodle; and they note that it was "sometimes known as KEEPING DOWN THE CENSUS."