Solid

bündig

(lacking errors or inconsistencies)

deftig

(extremely filling)

einfarbig

(of one color)

fest

(in the solid state)

fest

(large, massive)

kompakt

(lacking holes or hollows)

massiv

(large, massive)

robust

(strong, unyielding (as of foundations etc))

solide

(strong, unyielding (as of foundations etc))

zusammengeschrieben

(typography: written as one word)

Festkörper

(chemistry: fundamental state of matter)

Feststoff

(chemistry: fundamental state of matter)

Körper

(geometry: three-dimensional object)