talk through one’s hat

in. to say baseless things; to speak carelessly and tell lies. You don’t know what you are talking about. You’re just talking through your hat.

Name	Pronounced	Usage
Helga	['helgə]
Drahoslav	-	Czech, Slovak
Dipika	-	Indian, Hindi, Marathi, Kannada, Malayalam, Tamil, Telugu
Sibyl	SIB-əl	English
Dragoslav	-	Serbian, Croatian, Slovene, Medieval Slavic
Arabella	-	English