assassin - early 16th century: from French, from Italian assassino, from Arabic ḥašīšī ‘member of Nizari branch of Ismaili Muslims’, literally ‘hashish-eater’, probably originally a derogatory nickname, with reference to the supposedly erratic behaviour of the members of the sect, as if they were intoxicated by hashish.
avocado - The name avocado derives from the Nahuatl word ahuacatl, which refers to a certain part of the male anatomy that the shape of avocados happen to resemble (we're keeping this G-rated, folks).
jacuzzi - named after Candido Jacuzzi ( c. 1903–86), Italian-born American inventor.
quarantine - The name is from the Venetian policy (first enforced in 1377) of keeping ships from plague-stricken countries waiting off its port for 40 days to assure that no latent cases were aboard.
sandwich - named after the 4th Earl of Sandwich (1718–92), an English nobleman said to have eaten food in this form so as not to leave the gaming table.