the world > relative properties > kind or sort > individual character or quality > [adverb]
the world > relative properties > number > specific numbers > one > [adverb]
c1475 (?c1400) (1842) 8 It longiþ to þe gretnes of God to graunt singlerly þeis priuilegs.
1487 King Henry VII in H. Anstey (1898) II. 524 Wherby ye shall singlerly please us.