りくつ理屈rikutsu
1.

A way of thinking that prioritizes logical reasoning and rational explanations in understanding societal norms and realities, often contrasted with personal feelings or assumptions.

2.

A justification or rationale used to explain an opinion or action, which may appear well-structured but could be forced or artificial.

3.

The underlying principles or rules that account for why things are the way they are, often related to common sense or accepted truths.

4.

An explanation that may go beyond necessary reasoning, sometimes perceived as overly complicated or unnecessary for the situation at hand.

Example:

彼はその理屈がわからないほどばかではない。

へりくつ屁理屈herikutsu
1.

A reasoning or argument that is constructed more to defend one's own position than to adhere to logical principles, often perceived as arbitrary or contrived.

2.

A statement or interpretation that lacks sound reasoning or is based on illogical premises, typically used to justify a stance without genuine substantive support.

3.

A form of debate or discussion where the emphasis is placed on winning an argument rather than arriving at the truth, frequently characterized by trivial or overly complex distinctions.

Example:

屁理屈ばかり並べて、お前の言ってること全然筋が通ってないよ。

りくつ理屈rikutsuっぽいppoi
1.

Tending to express opinions or reasoning with excessive justification, often making discussions feel convoluted or overly analytical.

2.

Characterized by a propensity to explain or rationalize situations in a way that may seem unnecessarily complicated or pedantic.

3.

Inclined to emphasize logical reasoning or theories, sometimes to the detriment of straightforward communication or understanding.