The paper explores the mechanism of meaning ambiguity as illustrated by the German idiom-constructions Gott weiß / weiß Gott, using the methods of Ch. Fillmore’s construction grammar (C×G). The phraseoreflexes Gott weiß / weiß Gott are phraseological unit with a low degree of idiomaticity, with a stable, yet variable, composition, with a regular syntactic structure making it possible to define them a bigrammatical constructions. Syntactic elements such as actants and syntagms may complement the idiom-constructions Gott weiß / weiß Gott in the “minor syntax” category. The semantic meaning of the Gott weiß / weiß Gott slots changes depending on their type of syntactic complement. Incorporating the said phraseoreflexes as slots such as a simple sentence, an independent clause or a parenthesis into larger constructions makes them reveal their meaning ambiguity. The meaning ambiguity of the German phraseo-reflexes Gott weiß / weiß Gott is combined with distributive elements: the semantics (Sem) of the Gott weiß / weiß Gott slots changes depending on the type of the subordinate clause as their syntactic complement such as constructions with obclauses or the so-called w-clauses as a parenthesis or object dass-clauses. The phraseoreflex weiß Gott comprises the same “confirming” implicature used as an argument. The German phraseoreflexes Gott weiß / weiß Gott are examined in 101 contexts. The modification of a linguistic unit’s semantics becomes obvious when it is analyzed using the C×G methodology. This paper does not explore religious text types.