Assuming you are using Java 8+, you might use Stream.noneMatch like
String[] strings = zach.split("\\s+");
for (String s1 : strings) {
System.out.println(s1 + ": "
+ Stream.of(skoal).noneMatch(s -> s.equals(s1)));
}
And, \\s+ matches one (or more) whitespace in the regular expression.