Not logical or reasonable.

Lacking sound judgment; not based on reason.

तर्क के बिना

English Usage: Their irrational fears kept them from trying new things.

Hindi Usage: उनके तर्क के बिना डर ने उन्हें नई चीजें कोशिश करने से रोक दिया।

A person who is acting irrationally.

The state of being irrational.

तर्कहीनता

English Usage: The irrational of his arguments made it hard to take him seriously.

Hindi Usage: उसके तर्कों की तर्कहीनता उसे गंभीरता से लेना कठिन बनाती थी।