IPA: /ˈfɪəfʊlə/
KK: /ˈfɪrflər/
More afraid or anxious than someone or something else.
She felt fearfuller than ever when she heard the strange noise outside.
Fearfuller → It is formed from "fear" (from Old English "fǣr", meaning a feeling of anxiety or dread) and "-full" (meaning full of) combined with the comparative suffix "-er" (indicating a greater degree). The word "fearfuller" means more full of fear or more fearful than something else.
Think of someone who is 'full of fear' ('fear') and then imagine that they are even 'more' ('-er') afraid than before.
No commonly confused words.