insipid

dull or lacking flavor

Roots

im- / in- (not): not or without
sap / sav: taste, savor, or wisdom

Other words with the sap / sav root

sage: a wise person
sapid: having taste or flavor
sapience: wisdom or deep discernment
sapient: wise or possessing judgment
savor: to taste or enjoy fully

In- turns sapid off: insipid is not flavorful, then dull in spirit.

The lecture was technically correct but insipid.

Insipid begins as a taste word. If sapid has flavor, insipid lacks it. The exam meaning widens from food to prose, conversation, or ideas that feel flat.