This is the 571st most frequent Slovak word.
taký
"Such" or "like that."
Here, 'taký' is used to emphasize the degree of beauty of the day, translating to 'such [a]' in English.
To je taký pekný deň.
It's such a beautiful day.
In this sentence, 'taký' expresses a degree of emotion (sadness), equivalent to 'so' in English.
Prečo si taký smutný?
Why are you so sad?
Here, 'taký' characterizes a type or kind, and it means 'that kind of [person]' in English.