- Undercranking Noun Pres. Participle
- Undercroft Noun Adj
- Undercrossing Noun Adj
- Undercurrent Noun
- Undercut Noun Verb Past Participle
- Undercutter Noun Adj
- Undercutting Noun Pres. Participle
- Underdamping Noun Adj
- Underdeck Noun Adj
- Underdeclaration Noun Adj
- Underdefiniteness Noun
- Underdetermination Noun
- Underdevelopment Noun
- Underdog Noun Adj
- Underdose Noun Verb
- Underdrain Noun Verb Adj
- Underdrainage Noun Adj
- Underdrawers Noun
- Underdrawing Noun Adj
- Underdress Noun Verb
- Underdressing Noun Pres. Participle
- Underdrilling Noun Adj
- Underdrive Noun Verb Adj
- Underemployed Adj Noun Past Participle
- Underemployment Noun Adj
- Underenumeration Noun Adj
- Underestimate Verb Noun
- Underestimation Noun
- Underetch Verb Noun Adj
- Underetching Noun Adj
- Underexcitation Noun Adj
- Underexpansion Noun Adj
- Underexpenditure Noun Adj
- Underexporting Noun Pres. Participle
- Underexposing Noun
- Underexposure Noun Adj
- Underfeeding Noun Adj
- Underfelt Noun Adj
- Underfill Noun Verb Adj
- Underfilling Noun Adj
- Underfinancing Noun Pres. Participle
- Underfiring Noun Pres. Participle
- Underfishing Noun Pres. Participle
- Underfitting Noun Pres. Participle
- Underflooding Noun Pres. Participle Adj
- Underfloor Noun Adj
- Underflow Noun Verb Adj
- Underflying Pres. Participle Noun
- Underfocusing Noun Pres. Participle
- Underframe Noun Adj
- Underfrequency Noun Adj
- Underfulfillment Noun
- Underfunding Noun Adj
- Underfur Noun Adj
- Undergarment Noun Adj
- Undergarments Noun
- Undergirding Noun
- Underglaze Noun Verb Adj
- Undergraduate Adj Noun
- Undergrazing Noun Pres. Participle