EXTREMELY THIN can be described in many ways, such as GAUNT (5 letters), TENUOUS (7 letters), RAREFIED (8 letters), BONY (4 letters), and sizeone (7 letters). GAUNT implies a thinness that is almost skeletal, while TENUOUS suggests a delicate or fragile thinness. RAREFIED implies a thinness that is so extreme it is almost non-existent, and BONY implies a thinness that is visible due to the prominence of bones. Sizeone implies a thinness that is so extreme it is almost non-existent. All of these words describe EXTREMELY THIN in different ways, emphasizing the extreme nature of the thinness.