IPA: /ˈɔːfələr/
KK: /ˈɔːfələr/
More terrible or unpleasant than something else.
The weather today is awfuller than it was yesterday.
The word 'awfuller' is formed from 'awful' (from Old English 'egefull', meaning full of awe or fear) and the comparative suffix '-er' (meaning more). Thus, 'awfuller' means more full of awe or fear.
Think of something that is 'full of awe' ('awful') and then imagine it being 'more' ('-er') so that it becomes even more impressive or frightening.