romper

[rom-per] /ˈrɒm pər/
noun
1.
a person or thing that romps.
2.
Usually, rompers. (used with a plural verb)
  1. a loose, one-piece garment combining a shirt or blouse and short, bloomerlike pants, worn by young children.
  2. a similar garment worn by women and girls for sports, leisure activity, etc.
Origin of romper
1835-40; romp + -er1
British Dictionary definitions for rompers

rompers

/ˈrɒmpəz/
plural noun
1.
a one-piece baby garment consisting of trousers and a bib with straps
2.
(NZ) a type of costume worn by schoolgirls for games and gymnastics
Word Origin and History for rompers

romper

n.

1842, agent noun from romp (v.). Rompers "small children's overalls" first recorded 1909, on model of trousers.