If you didn't want to say someone is "inefficient", how would you concisely describe someone who has bad efficiency - badly/poorly efficient doesn't sound quite right, or is this ok?
- Anybody can ask a question
- Anybody can answer
- The best answers are voted up and rise to the top
Inefficient plainly is the most efficient word to use here, but if for some reason you prefer innuendo or euphemism, consider words or phrases like less than perfect, ineffective, fritterer, fiddler, unfocussed, overly meticulous, indirect, wasteful, roundabout.
As suggested in your comment to @Armen, saying Dan is not very efficient is a perfectly acceptable way (at least in British England) of saying that his efficiency is not very good. (In fact, it's the phrase I immediately thought of when reading your question and before reading the comments I mentioned.)