The term 'more costly' can be described by four different words: dearer (6 letters), steeper (7 letters), pricier (7 letters), and HIGHER (6 letters). Dearer is an adjective meaning more expensive, while steeper is an adjective meaning having a greater degree of difficulty or intensity. Pricier is an adjective meaning more expensive, and HIGHER is an adjective meaning greater in amount, degree, or number. All four words describe the same concept of something being more costly than something else.