"Under offer" means that a seller has received an offer from a potential buyer and is considering it, but the sale is not yet legally finalized. Negotiations may still be ongoing, and the property is not yet sold or taken off the market. It indicates that a buyer has made an offer that the seller has accepted in principle, but certain conditions, such as contracts, inspections, or finances, may need to be fulfilled before the sale is completed. The property can still be open to other offers unless a binding contract is signed later in the process.