Duler or Duller: How To spell?

The word Duler is misspelled against Duller, a noun meaning "One who, or that which, dulls."

Duller has double "ll" is mispronounced as "l"
Remember double 'LL' in between the strings du & er which should not be misspelled with single 'L'
Wrong Spelling:  du-l-er 
Correct Spelling:  du-ll-er 
Check more misspelled words of Duller to spell it correct.