たいへん大変taihen
1.

An indication of a significant or severe situation that requires serious attention or concern, often involving a drastic event or circumstance.

2.

Describes a state of affairs that is exceptionally challenging or difficult, implying considerable hardship or effort is necessary to address it.

3.

Reflects a condition that goes far beyond the ordinary level, conveying a sense of intensity or extreme degree in feelings or experiences.

Example:

1日中歩き回って大変疲れた。

だいへんか大変化daihenka
1.

A significant shift or transformation that has a profound impact on a situation or environment.

2.

A drastic alteration that results in a substantial departure from the previous state or condition.

だいへんかく大変革daihenkaku
1.

A significant and often sudden transformation in social, political, or economic structures that leads to a fundamental shift in established norms and practices.

2.

An overwhelming event or series of events that bring about profound changes, often resulting in upheaval or reorganization of various facets of society.

3.

A major alteration in the way systems operate, characterized by a comprehensive rethinking of strategies and approaches, frequently driven by necessity or a quest for improvement.

Example:

電話の発明は我々の生活に大変革をもたらした。

だいへんしん大変身daihenshin
1.

A significant transformation in appearance or style, often involving a dramatic alteration of one's outward persona.

2.

A profound shift in circumstances or status, reflecting a notable departure from a previous state.

3.

An extensive reformation, particularly in how one is perceived by others, leading to a new identity or image.

たいへんざんねん大変残念taihenzannen
1.

A profound sense of sorrow or regret over an unfortunate situation or outcome.

2.

A feeling of significant disappointment, often associated with unmet expectations or lost opportunities.

3.

An expression of heartfelt sadness regarding an event or circumstance that has turned out unfavorably.