Guile is the quality of being good at deceiving people in a clever way. I love children's innocence and lack of guile. the use of clever but dishonest methods to deceive someone = cunning
The Project GNU's extension language, it is a library that lets a programmer write extension modules to other programs Guile is an implementation of the Scheme programming language, but both the extension module and the original program to be extended can be written in other languages such as C, Tcl, etc