The phrase "pitched into" means to begin something with great energy or to engage in a task vigorously. Conversely, antonyms for this phrase would be words that convey a lack of commitment or enthusiasm in carrying out a task. Some appropriate antonyms include phrases such as "dragged my feet," "took my time," "phoned it in," or "half-heartedly attempted." In contrast to "pitched into," these antonyms denote a lack of energy, passion, or genuine effort in whatever task is being undertaken. While the phrase "pitched into" often implies a positive, aggressive action, its antonyms suggests a more apathetic or indifferent approach.