Thus from the √gna, gno = know, we have—
gna-rus = knowing.
i-gnarus (= in + gnarus) = ignorant.
nos-co (= gno-sco) = to get a knowledge of.
i-gno-sco = not to know, pardon.
no-bilis (= gno-bilis) = that can be known, famous, noble.
no-men (= gno-men) = a name.
To group together in this manner words of common origin and words closely associated in meaning is one of the best ways in which you can increase your vocabulary.
(For additional Examples of Cognates, see [Appendix IV.] pp. 287-8.)