'To con thanks' definitions:

Definition of 'To con thanks'

From: GCIDE

Con \Con\, v. t. [imp. & p. p. Conned; p. pr. & vb. n. Conning.] [AS. cunnan to know, be able, and (derived from this) cunnian to try, test. See Can, v. t. & i.]
1. To know; to understand; to acknowledge. [Obs.] [1913 Webster]
Of muses, Hobbinol, I con no skill. --Spenser. [1913 Webster]
They say they con to heaven the highway. --Spenser. [1913 Webster]
2. To study in order to know; to peruse; to learn; to commit to memory; to regard studiously. [1913 Webster]
Fixedly did look Upon the muddy waters which he conned As if he had been reading in a book. --Wordsworth. [1913 Webster]
I did not come into Parliament to con my lesson. --Burke. [1913 Webster]
To con answer, to be able to answer. [Obs.]
To con thanks, to thank; to acknowledge obligation. [Obs.] --Shak. [1913 Webster]