undergrow

From The Collaborative International Dictionary of English v.0.48:

Undergrow \Un`der*grow"\, v. i.
   To grow to an inferior, or less than the usual, size or
   height. --Wyclif.
   [1913 Webster]
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From The Collaborative International Dictionary of English v.0.48:

Undergrow \Un`der*grow"\, a.
   Undergrown. [Obs.] --Chaucer.
   [1913 Webster]