The verb σειω (seio) means to shake or move to and fro. In the classics this verb could describe the movement of trees in the breeze, teeth in an aged jaw, a spear in an angered hand, or a door swinging, chariots bouncing and of folks dancing to a catchy ditty. It could be used, very hip, to describe a shake-down (blackmail, extortion), or, also hip, in a Taylor Swift sense of shaking off of ideas and thoughts one doesn't like (but which, upon critical inspection, may not wholly be void of merit). But it would also describe the earth quaking (hence our English adjective seismic; see the noun σεισμος, seimos, below), or the mind being disturbed by anger or other intense emotions (and see for the cognitive equivalent of the hydrological cycle, our article on νεφελη, nephele, meaning cloud).

If this word is Indo-European, it's from a root that has left very few traces. But since the alphabet was imported from the Semitic Hebrews, perhaps a handy slew of terms were too (see our article on the many Hebrew roots of Greek). One particular verb of interest is סעה (sa'a), to rush (of a storm wind). But whatever the pedigree, our verb is used 5 times in the New Testament, see full concordance, and from it derive:

The verb τινασσω (tinasso) also means to shake, mostly in the sense of to shake loose or free. Homer used this verb to describe how Poseidon shook the boundless earth (Il.20.57), how Aphrodite shook Helen's scented robe (Il.3.385), how Eurymachos kicked his chair to smithereens (Od.22.88), hoe Zeus' monstrous eagles beat their wings (Od.2.151), and how the waves shattered Odysseus' raft (Od.5.368). Other authors spoke of quivering strings, of fruit shaken from a tree, of cumin beaten with a rod (the Septuagint's version of Isaiah 28:27).

It's entirely unclear where this verb comes from. There are very few words in Greek that start with τιν- (tin-), which suggests that these words may be foreign. One exception is the very common verb τινω (tino), meaning to pay a price (as penalty), from the verb τιω (tio), to pay honor, from which also comes the noun τιμη (time), meaning dearness (hence the name Timothy). The ultimate source of all these words is the Proto-Indo-European root "key-", meaning to pay or to avenge.

More attractive is the Hebrew verb נוע (nua'), meaning to shake, sway, reel or stagger. As we note above, many Hebrew terms were adopted into Greek, probably along with the alphabet, and perhaps this was one of them. In Isaiah 24:20 occurs the form תנוע (tanua'), "The earth shall reel to and fro like a drunkard."

Our verb τινασσω (tinasso) does not occur independently in the New Testament, but from it derive: