All 3 Uses of

scythe
in
Gulliver's Travels

Whereupon seven monsters, like himself, came towards him with reaping-hooks in their hands, each hook about the largeness of six scythes.†
Chpt 2

Her knives were twice as long as a scythe, set straight upon the handle.†
Chpt 2 *

scythe = a tool for cutting grass that has a curved blade and a long handle that is held with both hands

I used to attend the king's levee once or twice a week, and had often seen him under the barber's hand, which indeed was at first very terrible to behold; for the razor was almost twice as long as an ordinary scythe.†
Chpt 2

Definitions:

(1) (scythe)
a tool for cutting grass that has a curved blade and a long handle that is held with both hands

(See this Google Images link for scythe to see samples.)
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Much more rarely, scythe can be used as a verb to reference the cutting of weeds or tall grasses (such as hay or wheat) with a scythe. Metaphorically, the verb form can be used to describe cutting through anything as in "scythed through the problems in less than a week."