pronoun, genitive singular + emphatic particle (sandhi form)
Analysis. mama (genitive singular of ahaṃ 'I') + eva (emphatic particle 'alone, just, only'); the genitive mama becomes mam before eva through elision of final -a.
Etymology. ahaṃ is the nominative of the first-person singular pronoun, cognate with Sanskrit aham, Greek egō, Latin ego, English I (all from PIE *eg-). The emphatic particle eva is cognate with Sanskrit eva, from PIE *e-wi- (one, alone); it intensifies the pronoun to mean 'me alone' or 'only me'.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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