insufficient.

Too little in quantity, strength, or quality to meet a requirement.

Use it for

Words that belong together

• insufficient evidence
• insufficient capacity

On the page

The evidence was insufficient to establish a causal link.

Usage notes

Primary category: academic / formal. Forms: Comparative more insufficient; superlative most insufficient 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: analysis, evaluation. Commonness: moderately common.