- 2001 undefeated
- 2002 undefended
- 2003 undefensible
- 2004 undefide
- 2005 undefied
- 2006 undefiled
- 2007 undefinable
- 2008 undefined
- 2009 undefoliated
- 2010 undeformed
- 2011 undeified
- 2012 undeifies
- 2013 undeify
- 2014 undeifying
- 2015 undelayed
- 2016 undelaying
- 2017 undelectable
- 2018 undelegated
- 2019 undeliberate
- 2020 undelight
- 2021 undelighted
- 2022 undelightful
- 2023 undelights
- 2024 undeliverable
- 2025 undelivered
- 2026 undeluded
- 2027 undemanding
- 2028 undemocratic
- 2029 undemocratically
- 2030 undemonstrable
- 2031 undemonstrative
- 2032 undemonstratively
- 2033 undemonstrativeness
- 2034 undeniable
- 2035 undeniableness
- 2036 undeniably
- 2037 undenied
- 2038 undenominational
- 2039 undenominationalism
- 2040 undented
- 2041 undependable
- 2042 undependableness
- 2043 undepending
- 2044 undeplored
- 2045 undepraved
- 2046 undepreciated
- 2047 undepressed
- 2048 undeprived
- 2049 under
- 2050 underachieve
- 2051 underachieved
- 2052 underachievement
- 2053 underachiever
- 2054 underachieves
- 2055 underachieving
- 2056 underact
- 2057 underacted
- 2058 underacting
- 2059 underaction
- 2060 underactive
- 2061 underactivities
- 2062 underactivity
- 2063 underactor
- 2064 underacts
- 2065 underage
- 2066 underagent
- 2067 underages
- 2068 underappreciated
- 2069 underarm
- 2070 underate
- 2071 underbake
- 2072 underbaked
- 2073 underbakes
- 2074 underbaking
- 2075 underbear
- 2076 underbearer
- 2077 underbearing
- 2078 underbears
- 2079 underbellies
- 2080 underbelly
- 2081 underbid
- 2082 underbidder
- 2083 underbidding
- 2084 underbids
- 2085 underbit
- 2086 underbite
- 2087 underbiting
- 2088 underbitten
- 2089 underblanket
- 2090 underbodies
- 2091 underbody
- 2092 underbore
- 2093 underborne
- 2094 underboss
- 2095 underbough
- 2096 underbought
- 2097 underbreath
- 2098 underbred
- 2099 underbridge
- 2100 underbrim