Some references, such as the GLAAD Media Reference Guide, specifically recommend the spaced spelling (cis woman) and proscribe the unspaced spelling (ciswoman).
cis- + or cis + woman
cis woman (plural cis women)
- A cisgender woman.
- 2010, Holly Kearl, Stop Street Harassment: Making Public Places Safe and Welcoming for Women, Greenwood Publishing Group, →ISBN, page 57:
- Not only do people harass and attack transwomen for being who they are: transwomen also face scrutiny from both ciswomen and cismen over “what” they are.