What does baburrus mean in Latin?

baburrus, a adjective, means “foolish, silly”.

adjectivefirst/second-declension adjective

baburrus

baburrus (feminine baburra, neuter baburrum)

Ecclesiastical[baˈbur.rus]

singular
form	masculine	feminine	neuter
nominative	baburrus	baburra	baburrum
genitive	baburrī	baburrae	baburrī
dative	baburrō	baburrae	baburrō
accusative	baburrum	baburram	baburrum
ablative	baburrō	baburrā	baburrō
vocative	baburre	baburra	baburrum

plural
form	masculine	feminine	neuter
nominative	baburrī	baburrae	baburra
genitive	baburrōrum	baburrārum	baburrōrum
dative	baburrīs	baburrīs	baburrīs
accusative	baburrōs	baburrās	baburra
ablative	baburrīs	baburrīs	baburrīs
vocative	baburrī	baburrae	baburra

baburrus, a, um,

I. foolish, silly, Isid. Orig. 10, 31.

Of imitative origin, or perhaps connected to barbarus (“barbarian, foreign”). Compare babulus (“fool”), Ancient Greek βαβύρτας (babúrtas, “halfwit”).