Cutting input or output in a way that permanently discards content, with no mechanism to recover or reconstruct what was removed.

Carries its own confession in the first word, which is precisely why it appears in engineering documentation and never on the product page or the pricing tier.

• Honest Word, Hidden Placement: "Lossy" is entirely accurate and lives where customers do not read.
• Permanence Unstated: Nothing in the interface indicates the removal is irreversible.
• House-Cleaning Reality Check: Like a storage unit that disposes of a third of your boxes and writes "lossy storage" in a document you were never sent.

Eternal Sunshine of the Spotless Mind (2000s) where material is removed cleanly and the person carries on afterward with no sense that anything is missing.

“The context assembler applies lossy truncation above the configured threshold.”

“The system permanently dropped part of our input, and there is no way to see or recover what it removed.”