Yes, it is a real word. For example: 'He was unwilling to complete the task given'.
He was unwilling to do as he was instructed.
Refusal
unwilling to relent
resisting; unwilling
loath
You get the word idle.
Unwilling, disagreeable, unprepared.
loth
Averse.
The word reluctant is an adjective. It means to be unwilling.
Afraid
You get the word idle.