恣意的

1. Origins, structure, and basic meaning

• Structure: 恣意的 is read as しいてき and is a na-adjective meaning arbitrary, decided by personal preference or convenience rather than consistent grounds or standards.
• Basic usage: Avoiding arbitrary decisions appears in 恣意的な判断を避ける, while selectively choosing only part of the data appears in 一部だけを恣意的に選ぶ.

2. Common pitfalls and similar expressions

• Personal judgment replacing a standard
  • It is not a neutral statement that choice is free; it critically suggests that objective or consistent criteria are missing.
• Difference from 任意
  • Unlike the neutral term for something optional or left to one’s choice, this word criticizes a choice as lacking proper grounds.