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in·de·fat·i·ga·ble

(ĭn′dĭ-fătĭ-gə-bəl)

adj.

Having or showing a capacity for persistent effort; not tiring or relenting: See Synonyms at tireless.

[Obsolete French indéfatigable, from Latin indēfatīgābilis : in-, not; see IN-¹ + dēfatīgāre, to tire out (dē-, intensive pref.; see DE- + fatīgāre, to weary).]

in′de·fat′i·ga·bili·ty n.

in′de·fati·ga·bly adv.

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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