What term describes a decision made subject to individual discretion or sometimes impulse?

The term that describes a decision made subject to individual discretion or sometimes impulse is "arbitrary." When a decision is arbitrary, it suggests that it is based on personal choice or whim rather than established rules or reason. This implies that the decision may not follow a systematic approach, and rather, it is left to the individual's judgment or spontaneity.

In contrast, "volitional" pertains to the exercise of will or conscious choice but does not inherently indicate impulsiveness. "Deliberate" refers to decisions made with careful consideration and intention, which contrasts with the notion of randomness or impulsivity. "Calculated" implies that a decision is made after careful thought and assessment of potential outcomes, which also does not align with the idea of subjectivity or impulse.

Thus, "arbitrary" captures the essence of decision-making that lacks a definitive structure and is influenced by individual discretion.