A scythe was an item which could be used as a weapon. (TV: The Visitation)
The Father of Time carried a scythe, (COMIC: The Test of Time) as did Father Time in the Time Temple. Jamie McCrimmon took Father Time's scythe and used it to destroy several of his clock robots, the Second Doctor observing that the scythe must have been made of a metal much stronger than steel. (COMIC: Father Time)
Behind the scenes
Father Time uses the incorrect spelling "sythe".