demonstrative pronoun, masculine nominative singular (ayam) + genitive singular masculine (etassa, 'of him/this'). Surface form 'ayametassa' is a contraction or textual variant; resolves to 'ayam etassa' = 'this one's' or 'of this one'.
Analysis. ayam (this, demonstrative) + etassa (genitive of eta, him/it). In compounds and close collocations, the two words may run together in manuscript transmission. The phrase points to possession or attribution: 'this one's [quality/deed/consequence]'.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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