Duller

Dull'er noun One who, or that which, dulls.
Found on http://www.encyclo.co.uk/webster/D/130

Duller

• (imp. & p. p.) of Dull • (n.) One who, or that which, dulls.
Found on http://thinkexist.com/dictionary/meaning/duller/

duller

dull, duller, dullest, dullness, dullish 1. Intellectually weak or obtuse; stupid; mentally very slow. 2. Lacking responsiveness or alertness; insensitive. 3. Dispirited; depressed. 4. Not brisk or rapid; sluggish. 5. Not having a sharp edge or point; blunt; such as, a dull knife. 6. Not intensely or keenly felt; for example, a dull ache. 7. ...
Found on http://www.wordinfo.info/words/index/info/view_unit/3704/
No exact match found