ma·zel tov also ma·zal tov (mä'zəl tôf', tôv', tōv')
interj.
Used to express congratulations or best wishes.

[Mishnaic Hebrew mazzāl ṭôb, good luck : mazzāl, constellation, destiny (ultimately from Akkadian manzaltu, mazzaztum, position of a star, from izuzzu, to stand) + ṭôb, good.]

Definition:
The phrase mazel tov is a traditional Yiddish way to wish someone good luck, often used as a toast when drinking. It means "may your planetary influences be favorable" and, hence, derives from earlier beliefs in astrology.


Mazeltov
Mazeltov is a Yiddish word meaning "good luck" but is often used in place of "congratulations." Like other blessings it is often said frequently and sometimes loudly at Jewish weddings as well as Bar Mitzvahs. It is commonly used within the Jewish community. In colloquial languange, "Mazel tov" is sometimes said sarcastically when congratulations are not appropriate or due