Which phrase signifies a lack of wisdom in advice?

The phrase "armchair quarterback" signifies a lack of wisdom in advice because it refers to someone who offers opinions or criticism about a situation they are not directly involved in or do not fully understand. This expression originates from American football, where an "armchair quarterback" is someone who analyzes or critiques the game's strategy and decisions from the comfort of their seat rather than on the field, where the real action happens.

In this context, such an individual's advice may lack the relevancy or insight that comes from firsthand experience or practical involvement, leading to a lack of wisdom. The other phrases represent different concepts: "bloomer's advice" typically suggests someone acting too late or ineffectively, "mind the gap" is a warning about physical space or difference, and "barking up the wrong tree" refers to pursuing a mistaken or misguided course of action. None of these phrases directly point to an overall lack of wisdom in providing advice as effectively as "armchair quarterback" does.