(1 syl.). To suit or fit together, as, It won't fadge; we cannot fadge together; he does not fadge with me. (Anglo-Saxon, fægen, to fit together; Welsh, ffag, what tends to unite.)
“How will this fadge?”
Shakespeare: Twelfth Night, ii. 2.
A farthing. A corrupt contraction of fardingal, i.e. farthingale. (See Chivy.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894