Dictionaries are wonderful tools, but they can sometimes delude us into thinking words are more atomic than they really are.
Specific nouns are fairly self-contained and independent, and many general purpose verbs are as well.
What I will call here “modifiers” (for example, adjectives and adverbs in English) are where things start to get tricky, though, because they start webbing out into the forest of a language’s mental associations that cannot be easily cross-referenced.
Synonyms for “pretty”, for example, are loaded with nuance, and many would seem strange outside of various specific contexts.
This webs out into idioms, and in fact, in a language, there’s really no hard mental boundary between a word and an idiomatic phrase. Nor, really, a hard boundary between idiomatic and non-idiomatic phrases; just a continuum.
Natural languages are a reflection of our minds.