Thanks for the input, I was not sure about the 「大きい」either, it is better to remove it. However, for doushi, there is another noun「同志」. Is「同志」a suffix too?
For the differences between two Japanese words with the same pronunciation and similar meaning, Yahoo Answers is a surprisingly good resource. You can also do web searches like [[ 「同志」と「同士」の違い ]] to find explanation pages. In general homophonic kanji is an area that even native speakers struggle with sometimes, so there's lots of non-English coverage available.
https://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q10...
"「同志」と「同士」の意味の違いについて教えてください。"