The Collaborative International Dictionary of English v.0.48:

Rimer \Rim"er\, n.
   A rhymer; a versifier.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rimer \Rim"er\, n.
   A tool for shaping the rimes of a ladder.
   [1913 Webster]

The Devil's Dictionary (1881-1906):

RIMER, n.  A poet regarded with indifference or disesteem.

    The rimer quenches his unheeded fires,
    The sound surceases and the sense expires.
    Then the domestic dog, to east and west,
    Expounds the passions burning in his breast.
    The rising moon o'er that enchanted land
    Pauses to hear and yearns to understand.
                                                         Mowbray Myles