submarginal /sub-märˈji-nəl/

1. Near the margin
2. Below the minimum necessary
3. (of land) that cannot be farmed profitably

• undetermined
• undeterred
• undeveloped
• undeviating
• undeviatingly
• undevout
• undiagnosed
• undid
• undies
• undifferenced
• undifferentiated
• undigested
• undight
• undighting
• undights
• undignified
• undignifies
• undignify
• undignifying
• undiluted
• undiminishable
• undiminished
• unpunctuality
• unpunctuated
• unpunishable