Italian edit

Etymology edit

From attento +‎ -issimo.

Adjective edit

attentissimo (feminine attentissima, masculine plural attentissimi, feminine plural attentissime)

  1. superlative degree of attento
    1. very careful
    2. very attentive

Latin edit

Adjective edit

attentissimō

  1. dative/ablative masculine/neuter singular of attentissimus