What is General Issue?

Legal Definition
Pleading. A plea which traverses or denies at once the whole indictment or declaration, without offering any special matter, to evade it. It is called the general issue, because, by importing an absolute and general denial of what is alleged in the indictment or declaration, it amounts at once to an issue. 2 Bl. Com. 305.

2. The general issue in criminal cases, is, not guilty. In civil cases, the general issues are almost as various as the forms of action; in assumpsit, the general issue is non-assumpsit; in debt, nil debet; in detinue, non detinet; in trespass, non cul. or not guilty; in replevin, non cevit, &c.

3. Any matter going to show that a deed or contract, or other instrument is void, may be given in evidevce under the general issue; 10 Mass. 267, 274; 14 Pick. 303, 305; such as usury. 2 Mass. 540; 12 Mass. 26; 15 Mass. 48, 54. See 4 N. Hamp. R. 40; 2 Wend. 246; 6 Mass. 460; 10 Mass. 281. But a right to give evidence under the general issue, any matter which would avail under a special plea does not extend to matters in abatement. 9 Mass. 366: 14 Mass. 273; Gould on Pl. c. 4, pt. 1, ยง9, et seq.; Special Issue.
-- Bouviers Law Dictionary
Legal Definition
A plea or answer the effect of which is to traverse or deny all the material allegations of the declaration or complaint. See 94 Md. 290, 50 Atl. 1046.
-- Ballentine's Law Dictionary