66
boring(adjective, dreary, colorless, tedious, drab)
51
tedious(adjective, boring, uninteresting, dreary, monotonous)
47
flat(adjective, calm, quiet, set, hard)
45
dim(verb, adjective, action, characteristic, quiet)
43
tiresome(adjective, excite, slow, stupid, dry)
42
uninteresting(adjective, boring, tedious, dreary, monotonous)
41
slow(verb, adjective, stop, upset, trouble)
38
obtuse(noun, adjective, simple, sharp, slow)
37
dreary(adjective, excite, warm, unhappy, dark)
37
prosaic(adjective, set, weak, simple, tough)
36
monotonous(adjective, boring, uninteresting, uneventful, tedious)
35
stupid(adjective, simple, flat, rough, slow)
35
drab(adjective, characteristic, hard, weak, simple)
32
blunt(verb, adjective, action, quiet, check)
31
dead(adjective, hard, weak, simple, flat)
30
humdrum(adjective, weak, simple, excite, slow)
29
gloomy(adjective, characteristic, bad, obscure, flat)
29
lifeless(adjective, calm, weak, simple, tough)
29
wearisome(adjective, boring, tedious, dreary, lifeless)
26
insipid(adjective, hard, light, weak, kind)
<1234510>
2 years ago|80k views|share |citing 
APASmart Define. (2016). dull thesaurus. Retrieved August 20, 2018, from https://smartdefine.org/dull/thesaurus/synonyms
ChicagoSmart Define. 2016. "dull thesaurus" https://smartdefine.org/dull/thesaurus/synonyms (accessed August 20, 2018).
HarvardSmart Define 2016, dull thesaurus, Smart Define, viewed 20 August, 2018, <https://smartdefine.org/dull/thesaurus/synonyms>.
MLASmart Define. "dull thesaurus" 29 March 2016. Web. 20 August 2018. <https://smartdefine.org/dull/thesaurus/synonyms>