IPA: /ˈswɛltərɪŋ/
KK: /ˈswɛltərɪŋ/
Very hot and uncomfortable, often with high humidity.
The sweltering heat made it difficult to enjoy the outdoor picnic.
Comparative: sweltering
Superlative: most sweltering
Sweltering is derived from the Old English "sweltan" (meaning to die or perish) and the suffix "-ing" (indicating a process or action). The word describes the process of suffering from extreme heat, as if one is perishing from it.
Imagine the feeling of 'perishing' ('sweltan') from extreme heat — that's what sweltering means.