How should I write a regex to match a specific word?

I suggest bookmarking the MSDN Regular Expression Quick Reference

you want to achieve a case insensitive match for the word "rocket" surrounded by non-alphanumeric characters. A regex that would work would be:

\W*((?i)rocket(?-i))\W*

What it will do is look for zero or more (*) non-alphanumeric (\W) characters, followed by a case insensitive version of rocket ( (?i)rocket(?-i) ), followed again by zero or more (*) non-alphanumeric characters (\W). The extra parentheses around the rocket-matching term assigns the match to a separate group. The word rocket will thus be in match group 1.

UPDATE 1: Matt said in the comment that this regex is to be used in python. Python has a slightly different syntax. To achieve the same result in python, use this regex and pass the re.IGNORECASE option to the compile or match function.

\W*(rocket)\W*

On Regex101 this can be simulated by entering "i" in the textbox next to the regex input.

UPDATE 2 Ismael has mentioned, that the regex is not quite correct, as it might match "1rocket1". He posted a much better solution, namely

(?:^|\W)rocket(?:$|\W)

I think the look-aheads are overkill in this case, and you would be better off using word boundaries with the ignorecase option,

\brocket\b

In other words, in python:

>>> x="rocket's"
>>> y="rocket1."
>>> c=re.compile(r"\brocket\b",re.I)  # with the ignorecase option
>>> c.findall(y)
[]
>>> c.findall(x)
['rocket']