Perfect passive participle of rīdeō (“laugh”).

• (Classical Latin) IPA^(key): [ˈriː.sʊs]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈriː.s̬us]

rīsus (feminine rīsa, neuter rīsum); first/second-declension participle

1. laughed at, ridiculed, mocked, having been ridiculed

First/second-declension adjective.

rīsus m (genitive rīsūs); fourth declension

1. laughter, laughing

   Antonym: flētus

2. mockery, jest
3. practical joke, sport
   • 405 CE, Jerome, Vulgate Proverbs.10.23:

     quasi per rīsum stultus operātur scelus sapientia autem est virō prūdentia

     A fool worketh mischief as it were for sport: but wisdom is prudence to a man. (Douay-Rheims trans., Challoner rev.; 1752 CE)

4. smile

• Often used with "movere" (risum movere) to mean "make [someone] laugh".

Fourth-declension noun.

• “risus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “risus”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• "risus", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• risus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
• Carl Meißner, Henry William Auden (1894) Latin Phrase-Book‎^[1], London: Macmillan and Co.
  • to begin to laugh: risum edere, tollere
    
  • to raise a laugh: risum movere, concitare
    
  • to make a person laugh: risum elicere (more strongly excutere) alicui
    
  • to try and raise a laugh: risum captare
    
  • to be scarcely able to restrain one's laughter: risum tenere vix posse
    
  • to be scarcely able to restrain one's laughter: risum aegre continere posse
    
  • to make a thing ridiculous, turn it into a joke: aliquid in risum vertere