The 17th century Praxis Grammatica tells you how to give a bachelor a back-handed compliment:
[ 11 ] Unus vir est quasi nullus vir. [English Translation]
Praxis Grammatica gives great examples of Latin sentences in the guise of wondrously useful advice. Please feel free to post your interpretation of this bit of Latin and when it would be used.

Comments
Stating the obvious, eh? I like how you slid that editorial commentary in there
The phrase could have other intentions in mind too, though–like how sentries should be allocated to defend a castle, maybe.
I suppose I could have thought “a fish without a bicycle”, but I didn’t. Thanks for putting up a different interpretation. Makes sense.