Here are a couple of alternative ways of doing it, that may be faster or more suitable than KennyTM's answer, depending on the context.
1) use a regular expression:
import re
words_re = re.compile("|".join(list_of_words))
if words_re.search('some one long two phrase three'):
# do logic you want to perform
2) You could use sets if you want to match whole words, e.g. you do not want to find the word "the" in the phrase "them theorems are theoretical":
word_set = set(list_of_words)
phrase_set = set('some one long two phrase three'.split())
if word_set.intersection(phrase_set):
# do stuff
Of course you can also do whole word matches with regex using the "\b" token.
The performance of these and Kenny's solution are going to depend on several factors, such as how long the word list and phrase string are, and how often they change. If performance is not an issue then go for the simplest, which is probably Kenny's.