cantar

The everyday verb for to sing — cantar una canción (to sing a song) — and, colloquially, to stink or smell bad (este queso canta, this cheese reeks) or, in criminal slang, to confess or inform on someone (cantar ante la policía). Fully regular -ar conjugation.

• Ella canta muy bien. — She sings very well.
• Estos zapatos cantan a metros de distancia. — These shoes stink from a mile away.
• El testigo cantó todo ante el juez. — The witness spilled everything to the judge.

The slang senses (to stink, to confess/rat someone out) only work in casual or crime-related context — using cantar for 'to smell bad' in a formal setting will sound odd; oler mal is the neutral choice.

• book Cantar de mio Cid — The anonymous 12th-century epic poem, the earliest surviving major work of Spanish literature, uses cantar (song/chanson de geste) in its very title to name its genre — a sung or recited narrative of heroic deeds.
• book Cantar de los Cantares — The traditional Spanish title for the biblical Song of Songs (Song of Solomon), attributed to Solomon and one of the best-known books of the Old Testament's poetic wisdom literature.