knuckle down Synonyms

break one's back buckle down slave slave away spare no effort sweat blood work hard exert oneself slog away work one's guts out hustle work one's socks off get down to it be immersed in get down to pull out all stops put one's back into something get to work get one's act together hammer away sweat toil shape up keep one's nose to the grindstone peg away plug away beaver away labour apply oneself belly up to the bar pull up one's socks roll up one's sleeves burn the candle at both ends knock oneself out be busy as a bee