An “unpaid seller” under Sale of Goods Act, 1930 is a person

Section 45(1) of the Sale of Goods Act, 1930 makes a seller an "unpaid seller" "when the whole of the price has not been paid or tendered", or when a bill of exchange or other negotiable instrument received as conditional payment has been dishonoured.

The seller remains unpaid even if part of the price has been paid. A seller whose goods are unsold, or whose buyer has refused delivery, is not described by section 45, and a seller who has been paid is not unpaid.