Identify the part of speech the underlined word belongs to:
Certainof the candidates were well below the usual standard, but others were very good indeed.

Certain ( Pronoun):
Meaning: some
Ex: Certain of the candidates were well below the usual standard, but others were very good indeed.
Certain (adjective):
Meaning: having no doubt or knowing exactly that something is true, or known to be true, correct, exact, or effective:
Ex: I feel certain (that) you're doing the right thing.
Source: Cambridge Dictionary