Useful in an inferior capacity. / Obsequiously submissive.

Having a substance; actually existing. / Not imaginary; real; actual; true; veritable. / Corporeal; material; firm. / Having good substance; strong; stout; solid; firm.

Anything having substance; an essential part.

(of a sound, scientific) having a frequency too low to be audible / (of a sound, literary) very quiet, almost inaudible

an aircraft whose maximum speed is less than the speed of sound

(set theory) a set that is a subset of the set, but not equal to it.

(transitive) To assist (someone or something) by granting a subsidy.

(chemistry) a reaction in which one functional group is replaced with another

(chemistry) in aliphatic organic chemistry, a form of substitution reaction in which the leaving functional group is replaced with a nucleophile

(chemistry) in aromatic organic chemistry, a form of substitution reaction in which the leaving functional group (normally hydrogen) is replaced with an electrophile