The Collaborative International Dictionary
Efforce
Efforce \Ef*force\, v. t. [imp. & p. p. Efforced; p. pr. & vb.
n. Efforcing.] [OF. esforcier (F. s'efforcer to exert one's
self), LL. exforciare; L. ex + fortis strong. See Force.]
To force; to constrain; to compel to yield. [Obs.]
--Spenser.
Wiktionary
efforce
vb. 1 (context obsolete reflexive English) To force oneself. 2 (context obsolete transitive English) To force, force open; to acquire by force.