As an adjective muggier
is comparative of muggy.
As a noun mugger is
a street robber.
muggier
English
Adjective
(head)
(muggy)
muggy
English
Adjective
(er)
humid, or hot and humid.
Synonyms
* (of the weather) , oppressive, sultry
mugger
English
Etymology 1
Noun
(
en noun)
A street robber.
A person who makes exaggerated faces, as a performance; a gurner.
Etymology 2
From (etyl).
Noun
(
en noun)
A large crocodile Crocodilus palustris of southwest Asia, having a very broad wrinkled snout.