Synonyms for Trying (same or very similar meaning)
WordNet sense 1 (not easy; requiring great physical or mental effort to accomplish or comprehend or endure):
hardWordNet sense 2 (extremely irritating to the nerves):
nerve-racking, nerve-wracking, stressfulWordNet sense 3 (not to your liking):
disagreeableFrom the ODE community, based on WordNetadd/edit