Substances would work
It depends what kind of cold you are asking about. I would recommend searching a thesaurus: thesaurus.com is a place you could look.
2
Bang, bash, belt, bump, criticize, damn, ping, rap, roast, smash, sock, strike, tap, and whack are synonyms for knock.
You can use eggshells or shells
Some alternative words to use instead of "he" include: they, it, the person, the individual, one.
you can use or , otherwise, or rather than.
Acquired, obtained, received, or gained are alternative words that can be used instead of "got."
a or an
Some alternatives to "as" include "since," "because," "while," and "given that."
traitor
like
Instead of the phrase "freaked out", try:stunnedstartledalarmedpanicked
You could use words like us, we, our, ourselves.
smash
Like
things.