also sissy baby, sissy boy, sissy man, sissy pants, etc.) is a pejorative term for a boy or man who does not conform to "standard male" gender stereotypes.
Research published in 2015 suggests that the terms are asymmetrical in their power to stigmatize: sissy is almost always pejorative and conveys greater severity, while tomboy rarely causes as much concern but also elicits pressure to conform to normative gender roles. The Japanese word bishōnen is also a polite term for a man or boy with gentle or feminine attributes.
The word sissy in its original meaning of "sister" entered American English around 1840-1850 and acquired its pejorative meaning around 1885-1890; the verb sissify appeared in 1900-1905.
By the 1930s, "there was no more damning insult than to be called a sissy" and the word was widely used by American football coaches and sports writers to disparage rival teams and encourage ferocious player behavior.
The use of the word sissy was "ubiquitous" among delinquent American youth of the 1930s; the term was used to provoke boys to join gangs, demean boys who violated group norms, force compliance with the mandates of masculinity, and justify violence (including sexual violence) against younger and weaker children.
Good students were taunted as sissies and clothing styles associated with higher social classes were demeaned as sissified.
Among members of a Detroit youth gang in 1938-39, sissy was "the ultimate slur" used to tease and taunt other boys, as a rationalization for violence against rivals, and as an excuse for not observing the dictums of middle-class decorum and morality.
Thus, it appears that sissy served as a multi-functional insult, which was used not only to harass the person or group at whom it was directed, but also to reinforce gender stereotypes and gender binarism, assert men's dominance over women, disparage the weak and shy as well as the homosexual and transgender, penalize behavior that varied from gender norms, encourage aggressive behavior, and critique members of higher socioeconomic strata.
By the late 1980s, some men began to reclaim the term sissy for themselves.
over transgender students' use of school restrooms; in the episode a restroom initially designated for use by transgender students is later re-designated as "the cissy bathroom" for use by trans-phobic cisgender students.
Sissy (or sis) can also be a relationship nickname formed from sister, given to girls to indicate their role in the family, especially the oldest female sibling.
It can also be applied to girls as a term of affection from friends who are not family members.