'Encroacher' definitions:

Definition of 'encroacher'

From: WordNet
noun
Someone who enters by force in order to conquer [syn: invader, encroacher]

Definition of 'Encroacher'

From: GCIDE
  • Encroacher \En*croach"er\, n. One who by gradual steps enters on, and takes possession of, what is not his own. [1913 Webster]