Merriam-Webster Collegiate Dictionary - enjoin

 transitive verb  Etymology: Middle English, from Anglo-French ~dre, from Latin injungere, from in- + jungere to join — more at yoke  Date: 13th century  1. to direct or impose by authoritative order or with urgent admonition ~ed us to be careful  2.  a. forbid, prohibit was ~ed by conscience from telling a lie  b. to prohibit by a judicial order ; put an injunction on a book had been ~ed prior to publication — David Margolick  Synonyms: see command