strictly

In a strict manner.

He adhered strictly to the diet his doctor prescribed.

“If any pupil considers it acceptable to bring a pet into this school, let me tell you it is forbidden. Strictly forbidden!” pronounced the headmaster from the front of the class.

In a limited manner; only

This work was strictly voluntary, but any animal who absented himself from it would have his rations reduced by half.

In a narrow or limited sense.

That term refers strictly to smaller birds.

Scientific naming conventions are such that technically, ammonites are ammonoidean, ammonitidan, and sometimes strictly ammonitinan cephalopods.

In a manner that applies to every member of a set or every interval of a function

Strictly Come Dancing, a television show