In obsolete|lang=en terms the difference between smug and less
is that
smug is (obsolete) studiously neat or nice, especially in dress; spruce; affectedly precise; smooth and prim while
less is (obsolete) unless.
As adjectives the difference between smug and less
is that
smug is irritatingly pleased with oneself; self-satisfied while
less is .
As verbs the difference between smug and less
is that
smug is (obsolete|transitive) to make smug, or spruce while
less is (obsolete) to make less; to lessen.
As an adverb less is
to smaller extent.
As a preposition less is
minus; not including.
As a conjunction less is
(obsolete) unless.