closely

adverb2

1. •
   carefully, with attention to small details

   • Finnish and Estonian are closely related languages.
   • The borderline between East and West Berlin was very closely guarded.
2. •
   (no longer used) secretly; privately

   • That nought she did but wayle, and often steepe / Her dainty couch with tears which closely she did weepe. — 1590