What does "make a sissy of somebody" mean?

Question

In the movie "The power of the dog", a man talks to a boy that behaves like a sissy “Don’t let your mom make a sissy of you” (see the link about the movie here).

What does "make a sissy of somebody" mean?

Is it common in everyday English?

Answer 1

A sissy is a person (usually male) who acts in a way that the speaker considers effeminate, insufficiently "manly", or simply weak or cowardly. The term is in common use in US English. It can be used as anything from a mild tease to an intended serious insult. It is almost never intended as positive.

The idea that someone's influence can "make" a person, particularly a boy, into a sissy is not uncommon, although less common than it used to be.