Adverb

1. In a single or unaccompanied manner; without a companion.

   1901 The cross, reared now above all other objects, and standing singly out against the sky, was greeted with a burst of delight; and all who could see and read the writing upon the board over the Nazarene's head made haste to decipher it. Soon as read, the legend was adopted by them and communicated, and presently the whole mighty concourse was ringing the salutation from side to side, and repeating it with laughter and groans -"King of the Jews! Hail, King of the Jews!" — Lew Walllace, Ben Hur, Book 8, Chapter 10.

2. Individually; particularly; severally

   to make men singly and personally good

3. Without partners, companions, or associates; single-handed

   to attack another singly

4. Honestly; sincerely; simply.
5. Singularly; peculiarly.