This is the 381st most frequent Polish word.
znacznie
"Znacznie" means "significantly" or "considerably" in English.
Here, 'znacznie' acts as an adverb modifying the verb 'improve', meaning 'significantly'.
Znacznie poprawiła swoje wyniki w matematyce.
She significantly improved her math results.
In this sentence, 'znacznie' modifies the adjective 'larger', intensifying its degree, meaning 'much'.
To znacznie większy dom niż poprzedni.
This is a much larger house than the previous one.
'Znacznie' here describes the extent of being late, modifying the verb 'will be late', meaning 'considerably'.