Fate, destiny, fortune, portion.
First used in the English language in 1834, kismet originates from the Turkish qismet and the Arabic qismah or qismat meaning portion, lot or fate. The original root is qasama meaning “he divided”.
Why this word?
Majority of words in the English language come from Latin languages; these are long words with prolonged vowels, soft consonants and rolling-of-the-tongue pronunciations. This word comes from Arabic, from the Semitic languages, and it is characterized by short sounds and harsher consonants. Consider the softness of destiny and compare it to the hammer-like sound of kismet, sounds as if the two are not meant to represent the same notion.
“From a nation of enthusiasts and conquerors, the Osmanlis became a nation of sleepers and smokers. They came into Europe with the sword in one hand and the Koran in the other: were they driven out of their encampment, it would be with the Koran in one hand and the pipe in the other, crying: ‘Kismet! Kismet! Allah kehrim!’ (God hath willed it! God is great!) [Dr. James O. Noyes, "The Ottoman Empire," "The Knickerbocker," 1858]
Our English words don’t hint us on what destiny really is; it is a vague noun meaning that something is predetermined. Kismet on the other hand, stems from the verb to divide, reminding (some of) us the entity conducting over fate and destiny.
How to use kismet?
In the exact same way you would use destiny. “Being a teacher is my kismet”, “I’m so happy I met you, it is probably kismet!”