IPA: /ˌdɪs.rɪˈɡɑːrd.fəl/
KK: /dɪsˈrɪɡɑrdfəl/
Not paying attention to something or someone; showing a lack of consideration or care.
His disregardful attitude towards the rules caused many problems.
Disregardful → It is formed from "dis-" (meaning apart or away) and "regard" (from Old French *regarder*, meaning to look at or consider) and "-ful" (meaning full of). The word "disregardful" means full of not considering or looking at something.
Think of being 'away from' ('dis-') 'consideration' ('regard') — that's why disregardful means not considering something.