IPA: /ˈɪtʃ.i.ər/
KK: /ˈɪtʃiər/
Having a strong desire to scratch the skin due to irritation or discomfort, more so than usual.
After playing in the grass, I felt itchier than before.
Comparative: itchier
Superlative: itchiest
It is formed from "itch" (from Old English *icce*, meaning a sensation that causes a desire to scratch) and "-ier" (a comparative suffix indicating more). The word "itchier" means having a greater sensation of itch than something else.
Think of the sensation that makes you want to scratch ('itch') and remember that 'itchier' means having more of that sensation.