The thing is 姦 is first and foremost associate with sex, in particular bad kind of sex. It’s obvious from the compounds listed by Weblio: adultery 姦通, rape 強姦, incest 血族姦通. Now in Pleco (Chinese dictionary): to fornicate, adultery, rape.

So do your homeworks and stop spreading bullshit on the web: if the average Japanese or Chinese people stumble upon this character out of the very very restricted contexts it can mean something else, his first idea will be very bad. And in this case, in absence of okurigana, it’s clearly not one of those contexts.

Edit: I queried the BCCWJ Corpus with Shonagon, and there is not. a. single. use of 姦 as 姦しい over 673 results. Everything there is is compounds like 姦通、強姦罪、視姦者、姦淫、姦婦.