Some socially awkward types have the problem of being a bit too uneasy around certain types of people.
Alternatively, intimidation may result from the type of society in which individuals are socialized, as human beings are generally reluctant to engage in confrontation or threaten violence.
Cow implies bringing out an abject state of timorousness and often demoralization: a dog that was cowed by abuse.
To bully is to intimidate through blustering, domineering, or threatening behavior: workers who were bullied into accepting a poor contract.
An animal might intimidate a smaller animal by bearing its teeth, and a person can intimidate another by threatening to do something harmful.
Intimidation (also called cowing) is intentional behavior that "would cause a person of ordinary sensibilities" to fear injury or harm.