fray

To (cause to) unravel; used particularly for the edge of something made of cloth, or the end of a rope.

“The ribbon frayed at the cut end.”

To cause exhaustion, wear out (a person's mental strength).

“The hectic day ended in frayed nerves. (Metaphorical use; nerves are visualised as strings)”

Frighten; alarm

To bear the expense of; to defray.

To rub.

A fight or argument

“Though they did not know the reason for the dispute, they did not hesitate to leap into the fray.”

Fright.