The Collaborative International Dictionary
Imbrown
Imbrown \Im*brown"\, v. t. [Pref. im- in + brown. Cf. Embrown.] To make brown; to obscure; to darken; to tan; as, features imbrowned by exposure.
The mountain mass by scorching skies imbrowned.
--Byron.
Wiktionary
imbrown
vb. (archaic form of embrown English)