Disguise

Disable, disadvantage, disagree, disappear, discourage, disease, disgust… So many words start with the Latin prefix ‘dis’ meaning apart, away from, or off of. Today, the prefix ‘dis’ is also commonly used to mean opposite of, not, remove, and reverse.
 
What then is a dis + guise?
 
The word guise has its origins in the Proto-Indo-European (PIE) root weid (to see); which is also, by the way, the origin of the word video. PIE weid is the source of Proto-Germanic wison (appearance, form, manner) and Old High German wisa (manner, wise). A guise is the way in which something is seen.
 
The word guise appears in English in the late 13th century meaning a style or fashion of attire from Old French guise (manner, fashion, way).
 
And so, a ‘dis-guise’ is something that blocks or inhibits seeing.
 
The verb ‘to disguise’, from around 1300, meant to conceal the identity of a person by changes of usual appearance with the intention to deceive. Old French disguiser meant to change one’s appearance. By the mid-14th century, disguise meant to conceal or cover up the original character of someone or something by a counterfeit form or appearance.
 
The noun disguise, from around 1400, meant a strange style of dress intended to deceive. By the 1630s, a disguise was a false or misleading appearance intended for concealment of identity.
 
Reference: Online Etymological Dictionary, https://www.etymonline.com/