IPA: /ˈpeɪn.fəl/
KK: /ˈpeɪnfl/
Causing discomfort or suffering; something that hurts physically or emotionally.
The injury was so painful that I couldn't walk properly.
Comparative: more painful
Superlative: most painful
Painful → It is formed from "pain" (from Old French *peine*, meaning suffering or discomfort) and "-ful" (meaning full of). The word "painful" means full of pain or causing discomfort.
Think of 'pain' as suffering and remember that 'painful' means full of suffering.