1550s, "secretly," from close (adj.) + -ly (2). From 1560s as "compactly," 1590s as "so as to enclose;" 1630s as "nearly."
was closely involved in monitoring daily progress
the onsets were closely timed
houses set closely together
clop
Cloris
close
close quarters
closed
closely
closeness
closer
closet
close-up
closing
