| 1 | English | smug | Irritatingly pleased with oneself, offensively... |
| 2 | Low German | smuk | — |
| 3 | Middle Low German | smuk | lithe, neat; lithe, delicate, neat, trim;... |
| 4 | Proto-West Germanic | smeugan | to creep, to crawl |
| 5 | Proto-Germanic | *smeuganą | — |
| 6 | Proto-Indo-European | (s)mewk- | to let loose, release; to slip away, escape, flee |
| 7 | Proto-Indo-European | smewg- | to slip, glide, slide; to slip, glide; be slimy |