Ambustus was a cognomen that distinguished a patrician branch of the gens Fabia. "Ambustus" was Latin for "burnt".
Prominent members of this family include:
Quintus Fabius M. f. Q. n. Vibulanus Ambustus, consul in 412 BC.
Marcus Fabius Q. f. Q. n. Ambustus, pontifex maximus in 390 BC.
Caeso Fabius M. f. Q. n. Ambustus, tribunus militum consulari potestate in 404, 401, 395, and 390 BC.
Numerius Fabius M. f. Q. n. Ambustus, tribunus militum consulari potestate in 406 and 390 BC.
Quintus Fabius M. f. Q. n. Ambustus, tribunus militum consulari potestate in 390 BC.
Marcus Fabius K. f. M. n. Ambustus, tribunus militum consulari potestate in 381 and 369 BC, and censor in 363; supported the lex Licinia Sextia, which granted the plebeians the right to hold the consulship.Fabia M. f. K. n., daughter of the above, married Servius Sulpicius Praetextatus, tribunus militum consulari potestate in 377, 376, 370, and 368 BC.
Fabia M. f. K. n., daughter of the above, married Gaius Licinius Calvus Stolo, consul in 364 and 361 BC.
Marcus Fabius N. f. M. n. Ambustus, consul in 360, 356, and 354 BC, princeps senatus triumphed over the Tiburtines.
Gaius Fabius N. f. M. n. Ambustus, consul in 358 BC.
Marcus Fabius M. f. N. n. Ambustus, magister equitum in 322 BC.
Quintus Fabius Ambustus, nominated dictator in 321 BC, but compelled to resign due to a fault in the auspices.
Gaius Fabius M. f. N. n. Ambustus, appointed magister equitum in 315 BC, in place of Quintus Aulius, who fell in battle.