Fray
/fɹeɪ/
verb
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