"act of taking food," Old English feding, verbal noun from feed (v.). Feeding frenzy is from 1989, metaphoric extension of a phrase that had been used of sharks since 1950s.
1790, "to tend, guard, and watch sheep," from shepherd (n.). The metaphoric sense of "watch over or guide" is attested by 1820. Related: Shepherded; shepherding.
1938, "anti-aircraft gun," from German Flak, condensed from Fliegerabwehrkanone, literally "pilot warding-off cannon." Sense of "anti-aircraft fire" is from 1940; metaphoric sense of "criticism" is c. 1963 in American English. Flak jacket is by 1956.
late 14c., "to choke, suffocate, drown," of uncertain origin, possibly an alteration of Old French estouffer "to stifle, smother" (Modern French étouffer), itself of uncertain etymology, perhaps from a Germanic source (compare Old High German stopfon "to plug up, stuff"). Metaphoric sense is from 1570s. Related: Stifled; stifling.