'Obscure' in the Bible

For you are sent to the house of Israel, not to a people {of obscure speech} and {of a difficult language},

[and] not to many nations {of obscure speech} and {a difficult language} {whose words} you do not understand, [for] if I had sent you to them they would have listened to you.

behold, thou art wiser than Daniel! nothing secret is obscure for thee;