IPA: /ruːˈtiːnli/
KK: /ruːˈtiːnli/
In a way that is done regularly or as part of a usual practice, often without much thought.
She exercises routinely to stay healthy.
Routinely → It is formed from "route" (from Old French *route*, meaning a way or path) and the suffix "-ly" (meaning in a manner of). The word "routinely" means in a manner that follows a regular path or way, indicating habitual actions.
Think of following a 'path' ('route') regularly — that's why 'routinely' means doing something in a habitual manner.
No commonly confused words.