Just now I was certain that there must be a ‘c’ somewhere it the word ‘antique’…but apparently not.
There is a ‘c’ in ‘certain’, however, which is perhaps more baffling. If you pronounce it with a hard ‘c’ it becomes ‘ker-tin’.
This leads me to think that the word ‘curtain’ really ought to be used in a metaphor for understanding…and the word ‘curtainty’ should be coined to refer to the general application of drapes.