The phrase "fiddled about" can be used to describe someone who is wasting time or not being productive. There are many synonyms that can be used in place of this phrase to convey the same meaning. For instance, "lollygagged", "dawdled", "idled", "piddled", "wasted time", "killed time", "loitered", "wasted away", "procrastinated" and "lounged". These words all imply someone who is not using their time wisely and could be doing something more productive instead. Whether you use "fiddled about" or one of these synonyms, the message is clear: time is a valuable resource that should be used wisely.