What is the meaning of -eth?

Used to form the third-person singular present indicative of verbs.

Used broadly with various verb forms for ironic pseudoarchaic or pseudoecclesiastical effect.

used to create ordinal numbers from cardinal numbers ending in -y, namely the multiples of ten (other than ten itself): 20, 30, 40, 50, 60, 70, 80, and 90; e.g. twentieth, thirtieth.

Forms abstract nouns

Used to form the third-person singular present indicative of verbs (other than preterite-presents).

1 2 “-eth, suf.(2).”, in MED Online, Ann Arbor, Mich.: University of Michigan, 2007.

1 2 McIntosh, Angus; Samuels, M[ichael] L.; Benskin, Michael (2013) [1986], Michael Benskin, Margaret Laing, editors, eLALME: A Linguistic Atlas of Late Medieval English‎, Edinburgh: Angus McIntosh Centre for Historical Linguistics; revised November 2024.

↑ Dobson, E[ric] J. (1957), English pronunciation 1500-1700‎, second edition, volume II: Phonology, Oxford: Clarendon Press, published 1968, →OCLC, § 311, page 880.

↑ Jordan, Richard (1974),  Eugene Crook, transl., Handbook of the Middle English Grammar: Phonology (Janua Linguarum. Series Practica; 218)‎, The Hague: Mouton & Co. N.V., →DOI, § 291, page 246.

Used to form the present indicative and imperative plural of verbs.

↑ “-eth, suf.(2).”, in MED Online, Ann Arbor, Mich.: University of Michigan, 2007.

1 2 McIntosh, Angus (1983), “Present Indicative Plural Forms in the Later Middle English of the North Midlands”, in Douglas Gray, E. G. Stanley, editors, Middle English Studies Presented to Norman Davis in Honour of his Seventieth Birthday, Oxford: Clarendon Press, →ISBN, →OCLC, pages 235-244; reprinted 1985.

↑ McIntosh, Angus; Samuels, M[ichael] L.; Benskin, Michael (2013) [1986], Michael Benskin, Margaret Laing, editors, eLALME: A Linguistic Atlas of Late Medieval English‎, Edinburgh: Angus McIntosh Centre for Historical Linguistics; revised November 2024.

alternative form of -the (abstract nominal suffix)

alternative form of -the (ordinal suffix)

Source: wiktionary.org