Customary way of speaking or acting; fashion, manner, practice (often used formerly in such phrases as "at his own guise"; that is, in his own fashion, to suit himself.)
"In the chatroom, he signed his posts as 'guise' to avoid being banned for spamming."
Deliberate misspelling of guys.
To dress.
"The spy changed his disguise to a plain suit so he could walk undetected through the city streets."
A surname.
"The detective realized that the man known as Guise was actually a notorious con artist operating under an alias."