prohibitive.

1. So high or difficult that it effectively prevents someone from doing something.

2. Serving to forbid or stop a particular action.

Use it for

Words that belong together

• prohibitive cost
• prohibitive expense

On the page

The prohibitive cost of transport made the cheaper equipment unusable.

Usage notes

Primary category: academic / formal. Forms: Comparative more prohibitive; superlative most prohibitive 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. Commonness: moderately common.