amañar

To rig, fix, or tamper with an outcome dishonestly — amañar un partido, amañar las cuentas, amañar unas elecciones. It always carries a negative connotation of manipulation or fraud, unlike neutral words for 'arranging' something.

• Los jugadores fueron acusados de amañar el resultado. — The players were accused of fixing the result.
• Denunciaron que habían amañado las cuentas de la empresa. — They reported that the company's accounts had been tampered with.
• El escándalo estalló cuando se supo que amañaron la licitación. — The scandal broke when it came out that the bidding process had been rigged.

Using amañar as a neutral synonym for 'arrange' or 'fix' (as in repair) — it always implies dishonest manipulation; for a neutral fix, arreglar is the right word.

Often confused with arreglar.

• politics "Elecciones amañadas" — A standard, widely used Spanish-language political phrase for "rigged elections," built from the past participle of amañar, used across Spanish-speaking media to describe electoral fraud.