apostillar

In everyday usage, to add a brief note or comment to a text, often clarifying or qualifying something already said (apostilló que no estaba del todo de acuerdo). Separately, in legal/administrative contexts it's used for apostilling a document — certifying it under the 1961 Hague Apostille Convention for international recognition.

• El editor apostilló el artículo con una aclaración. — The editor added a note to the article with a clarification.
• Hay que apostillar el certificado antes de enviarlo al extranjero. — The certificate needs to be apostilled before sending it abroad.
• Apostilló que sus palabras se habían malinterpretado. — He added the remark that his words had been misunderstood.

Not realizing this verb has two fairly distinct senses — a general 'add a comment' meaning and a specific legal 'certify with an apostille' meaning — context (a text vs. an official document) is what tells them apart.