anodyne
Concise Oxford English Dictionary © 2008 Oxford University Press:
anodyne /ˈanədʌɪn/
▶adjective unlikely to cause offence or disagreement but somewhat dull. ▶noun a painkilling drug or medicine.
– origin C16: via L. from Gk anōdunos ‘painless’.
'anodyne' also found in these Oxford entries:

