To task too heavily, to give someone or something to many tasks; overburden(verb)
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Use "overtask" in a sentence
"Operation comes to overtask us, either through the admixture of useless matters, or through the multiplicity of instruments, or through the bulk of the material and of the bodies that may happen to be required for any particular work."
"In the latter years of his life he was known to overtask himself; and at length the body gave way, though the mind remained firm to the last."
"Though such an important chief, he is the meanest dressed of his subjects, — is always filthy, — ever greasy — eternally foul about the mouth; but these are mere eccentricities: as a wise judge, he is without parallel, always has a dodge ever ready for the abstraction of cloth from the spiritless Arab merchants, who trade with Unyanyembe every year; and disposes with ease of a judicial case which would overtask ordinary men."