Blunder dream meaning is explained below using 3 different sources. Each interpretation is shown with its source.

Interpretation 1 — Ibn Seerin

(Foolish talk, Nonsense, or people’s foolish talk) Blunder in a dream means disobedience, sin or refusing to accept a good advice.

To make a foolish oath in a dream means repentance of a sinner and guidance for a disbeliever.

(Also see Grammarian, Fool, Linguist, Lying)

Source: Islamic Dream Interpretation Author: Ibn Seerin

Interpretation 2 — Internet Archive - Anonymous

This is one of the dreams that go by “ contraries “ and means that you will do unexpectedly well in your next undertaking.
Source: Mystic Dream Book Author: Internet Archive - Anonymous

Interpretation 3 — Stearn Robinson - Tom Corbett

A dream of contrary, and the more clumsy and awkward the dream action was, the greater will be your success.
Source: The Complete Guide to Interpreting Your Dreams Author: Stearn Robinson - Tom Corbett