temperamental.

1. Prone to unpredictable changes of mood or behavior.

2. Working inconsistently or unpredictably.

Use it for

Words that belong together

• temperamental character
• temperamental response

On the page

The director's temperamental manner made rehearsals uneasy.

Usage notes

Primary category: psychology / human behavior. Forms: Comparative more temperamental; superlative most temperamental when comparison is meaningful. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: character, behavior. Commonness: moderately common.