bite into/off

nail biting

(of pets, animals, etc...) play biting

Same as above.

to force someone to clamp with their teeth, to force into someone's mouth (e.g. a gag) / to wedge into a space / to inflict (a blow), to deal (a hit)

to chew, to digest / to fully appreciate, to fully understand

(literally) To bite one's own navel / (idiomatic) To be deeply regretful about something

passive, inactive, timid

not always, not necessarily / not completely / not exactly, not strictly speaking, not technically

stiffen / for a person to freeze, for one's expression to freeze