Term mostly used in the UK. When one is averse to overt displays of gore and blood, particularly of the kind displayed in violent/teen slasher films/medical dramas, or when subjected to them in real life (e.g. an accident, dissecting an organ in school) is likely to faint or be sick. Can also include dislike and strong desire to avoid images of violence or pain, such as injecting oneself.
I couldn't bear to see that horror movie....I'm far too squeamish!!