keeps nose to the grindstone (verb) keep one's nose to the grindstone: work doggedly
Sinonime: bullheaded,
cantankerous,
contrary,
difficult, disobedient, headstrong,
incorrigible,
intractable,
opinionated,
perverse,
rebellious,
stubborn, ungovernable, unmanageable, unresponsive, unruly,
unyielding, willful
Antonime: manageable,
obedient