Codger

from WordNet (r) 3.0 (2006)

codger
    n 1: used affectionately to refer to an eccentric but amusing
         old man [syn: {codger}, {old codger}]

from The Collaborative International Dictionary of English v.0.48

Codger \Codg"er\, n. [Cf. {Cadger}.]
   1. A miser or mean person.
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   2. A singular or odd person, especially an old man; -- a
      familiar, humorous, or depreciatory appellation. [Colloq.]
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            A few of us old codgers met at the fireside.
                                                  --Emerson.
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