gnaw
chow
A four letter word meaning not kosher is: tref
Gnawed - To bite or chew.
What is a nine letter word meaning very tidy
The word pine can have that meaning.
ruminate
Stare
A similar meaning to masticate is the word: chew.
chew
chomp
Chew
chow
Regard means to gaze at steadily
chew
Steadily is an adverb.
more steadily, most steadily
champ, chomp, chump, munch