obsum

From ob- (“against”) +‎ sum (“to be”).

• (Classical Latin) IPA^(key): [ˈɔp.sũː]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈɔb.sum]

obsum (present infinitive obesse, perfect active obfuī, future active participle obfutūrus); irregular conjugation, suppletive, no passive, no supine stem except in the future active participle, no gerund

1. (with dative) to be against, be prejudicial to, be opposed to
   • 8 CE, Ovid, Fasti 4.309–310:

     cultūs et ōrnātīs variē prōdīsse capillīs
     obfuit, ad rigidōs prōmptaque lingua senēs

     Her elegance was against her, and that she went about with variously ornate hairstyles,
     together with her ready retorts to the strict old men.
     (See Claudia Quinta.)

2. to hinder, get or be in the way
   • 166 BCE, Publius Terentius Afer, Andria 159–160:

     SĪMŌ: Simul, scelerātus Dāvus sī quid cōnsilī / habet, ut cōnsūmat nunc cum nīl obsint dolī.

     SIMO: At the same time, if that wicked Davus has thought of some scheme, he may squander it now when his tricks won’t be a hindrance.
     Or, …when his tricks will do no harm.

3. to hurt, injure, do harm to

¹Old Latin or in poetry.

• “obsum”, in Charlton T. Lewis and Charles Short (1879), A Latin Dictionary, Oxford: Clarendon Press
• “obsum”, in Charlton T. Lewis (1891), An Elementary Latin Dictionary, New York: Harper & Brothers
• “obsum”, in Gaffiot, Félix (1934), Dictionnaire illustré latin-français, Hachette.