A great source of learning and improving Latin is Gradus ad Parnassum. It is a 17th century thesaurus of synonyms and epithets for nouns that was circulating in Europe for centuries for his value. To get a glimpse of its value, let look under peccatum. we find:

Synonyms: delictum, noxa, culpa, crimen, scelus, flagitium, vitium, piaculum, nefas, error, erratum, malum.
Epithets: Nefandum, turpe, foedum, grave, inexcusabile, detestabile, execrabile, infandum, dirum, grande, ingens, noxium, impium, atrox.
Alternative ways to convey the same meaning are also suggested: Ausa nefanda; Factum turpe; Res odiosa Deo; Foedae contagia labis; Sceleratae crlmina vitae; Detestanda lues; et inexcusabile crimen.

The Latin phrase gradus ad Parnassum means “steps to Parnassus”. It is sometimes shortened to gradus. The name Parnassus was used to denote the loftiest part of a mountain range in central Greece, a few miles north of Delphi, of which the two summits, in Classical times, were called Tithorea and Lycoreia. In Greek mythology, one of the peaks was sacred to Apollo and the nine Muses, the inspiring deities of the arts, and the other to Dionysus. The phrase has often been used to refer to various books of instruction, or guides, in which gradual progress in literature, language instruction, music, or the arts in general, is sought. (Wikipedia)

A paperback edition containing English meanings can be found here