3rd person plural optative (potential mood) of nikkhipati; the form nikkhipeyyuṁ shows sandhi contraction (-eyy- + -uṁ)
Analysis. nis- (out of, away from) + khipati (throws); literally 'throws away', hence to deposit, set aside, or abandon.
Etymology. The prefix nis- (out of, away from) + √khip (throw). The root √khip is cognate with Sanskrit kṣipati and ultimately with Greek skhedios (hasty, sudden). The concrete image of throwing away underlies the range from 'depositing' to 'abandoning'.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
Lite mode — plain HTML for e-readers and old browsers. Full version