Use 'inconsiderate' when someone ignores social norms or etiquette, causing annoyance or offense. Talking loudly on your phone in a quiet cafe is inconsiderate.
Pro Tip 2/3
Neglect of Feelings
'Inconsiderate' often implies neglecting others' feelings in favor of one's own comfort or convenience. Playing loud music late at night is inconsiderate to neighbors.
Pro Tip 3/3
Impact of Words
Calling someone 'inconsiderate' can be strong criticism. Use with care to avoid offending. She called him inconsiderate for forgetting her birthday.