in a stringent manner
"the laws are stringently enforced"
"stringently controlled"
In a strict manner.
"The coach strictly enforced the new training rules, leaving no room for exceptions during practice."
In plain English: Strictly means doing something exactly as planned without any extra rules or changes.
"The teacher asked us to strictly follow the school rules."
Strictly Come Dancing, a television show
"My cousin has been watching Strictly Come Dancing every week since it started airing on Saturday nights."
Strictly comes from combining the word strict with the suffix -ly. It entered English as an adverbial form to indicate that something is done in a precise or rigid manner.