Stupid or foolish; resembling or characteristic of a chump; also, chunky or lumpy in texture.
From chump with the adjectival suffix -y, creating an informal adjective with dual meanings of foolish and physically chunky.
Chumpy is delightfully versatile—you can use it to describe both a foolish person's behavior and the texture of overly chunky peanut butter, showing how informal English lets single words expand into different semantic territories.
Complete word intelligence in one call. Free tier — 50 lookups/day.