This is the 920th most frequent Turkish word.
sıkı
"Tight" or "strict."
Here, 'sıkı' describes a physical state of being tight or snug-fitting.
Bu pantolon çok sıkı oldu.
These pants became very tight.
In this sentence, 'sıkı' is used to describe diligence or intensity of effort.
Sıkı çalışırsan başarılı olursun.
If you work hard, you will succeed.
Here, 'sıkı' conveys the meaning of a close or strong relationship.