1) tested and known to be true, successful (proven)
2) based on theory, not on practice or experience; not tested yet (theoretical)
3) not tested (untired)
put to particular use
used
incapable of failure, involving no risk
infallible
able, skilful
able, skilful
of try
reliable
genuine and acceptable because made or done with the correct formalities; that can be legally used; (of arguments, reasons etc) acceptable
right, genuine
