pubescent

One s sound in the middle of pubescent is carried by two letters, s and c, and the front of the word turns a single u into pyoo. Five spellings are filed here and all of them come from one of those two facts.

Covered in short soft hairs, downy to the touch. Mullein and many sages are pubescent enough to feel like felt.

Latin pubescere meant to grow downy, to come of age, and pubescens is its present participle. The -escent that ends it is a suffix of becoming, the same one in incandescent, effervescent and convalescent, and it always carries an sc. In English the c of that pair is soft, so both letters together deliver a single s.