Your line words = open("../WordsForGames.txt")does not read the file, it simply opens it for reading or, possibly, writing, if you add additional flags.
You need, for example, to read a line or lines with readlines(), and then, most likely, break the words into a list, and then randomly select one of the words. Something like that:
import random
lines = open("../WordsForGames.txt").readlines()
line = lines[0]
words = line.split()
myword = random.choice(words)