From Middle English senglely.

• IPA: /ˈsɪŋ.ɡli/

singly (not comparable)

1. In a single or unaccompanied manner; without a companion.
   • 1651, Thomas Hobbes, chapter I, in Leviathan, or The Matter, Forme, & Power of a Common-wealth Ecclesiasticall and Civill, London: […] [William Wilson] for Andrew Crooke, […], →OCLC ↗:

     Singly, they are every one a representation or appearance of some quality, or other accident of a body without us, which is commonly called an object.

   • 1880 November 11, Lew[is] Wallace, chapter 10, in Ben-Hur: A Tale of the Christ, New York, N.Y.: Harper & Brothers, […], →OCLC ↗:

     The cross, reared now above all other objects, and standing singly out against the sky, was greeted with a burst of delight; […]

   • 1881–1882, Robert Louis Stevenson, “13: How My Shore Adventure Began”, in Treasure Island, London, Paris: Cassell & Company, published 14 November 1883, →OCLC ↗:

     Grey-coloured woods covered a large part of the surface. This even tint was indeed broken up by streaks of yellow sand-break in the lower lands, and by many tall trees of the pine family, out-topping the others—some singly, some in clumps […]

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. (obsolete) Singularly; peculiarly.

• (without a companion) alone, solo; see also Thesaurus:solitarily
• (individually) discretely; see also Thesaurus:individually
• (without partners) unassisted; see also Thesaurus:by oneself
• (honestly) truly, truthfully; see also Thesaurus:honestly
• (peculiarly) oddly; see also Thesaurus:strangely