To work one's tail off slang verb phrase
To work extremely hard
I admire those who have worked their tails off to succeed rather than those coming from well-off families or inheriting family fortunes.
Despite working her tail off, she hasn't achieved much in her career.
To work very hard for something
An industrious person
Very busy
Show signs of great and arduous efforts or labour on study or tasks leading to the result of tiredness and lack of vitality.
Someone is extremely boring, often due to being very studious or introverted.
The verb "work" must be conjugated according to its tense.
This phrase is traceable to the first half of the twentieth century. James Farrell used it in Studs Lonigan (1932–35): “This idea of sweating your tail off with work.”