Synonymy and precise word choice

Synonyms are not interchangeable

Two words rarely differ in nothing. They differ in register, in intensity, in what they combine with, or in where they came from. A synonym dictionary gives you the set; deciding within it is the skill.

Register

Хата is listed as colloquial, but that undersells it: it is also the warm and culturally central word, which is why свая хата works where сваё жытло would be absurd.

Intensity

Sets that climb: непакоіцца - хвалявацца - трывожыцца - панікаваць; падабацца - любіць - кахаць. That last one is a real distinction and not a matter of degree: кахаць is romantic love only, любіць covers everything else, including people, places and food. Using кахаць about your mother is a mistake a learner makes once.

Collocation

Near-identical words take different partners. Моцны and дужы both mean strong, but моцны takes чай, вецер and мароз, while дужы belongs to people and animals. Nothing in the definitions tells you this; only the usage does.

Origin as a dimension

Because Belarusian has a Polish layer and a Slavic inherited layer, many concepts have one word from each, and they are rarely equal in feel: крама alongside магазін, гарбата alongside чай, ровар alongside веласіпед. The Polish-layer word tends to read as the more distinctly Belarusian choice, and in most independent writing it is the default.

The test

Three questions before you commit: does this word fit the register of the sentence around it? Is it the right strength? Does it collocate with the words on either side of it? If you cannot answer the third, look the word up in a real sentence rather than a dictionary entry.