INANELY
fatuously, inanely
(adverb) vacuously or complacently and unconsciously foolish
Source: WordNet® 3.1
Etymology
Adverb
inanely (comparative more inanely, superlative most inanely)
In an inane manner.
Source: Wiktionary
INANE
In*ane", a. Etym: [L. inanis.]
Definition: Without contents; empty; void of sense or intelligence;
purposeless; pointless; characterless; useless. "Vague and inane
instincts." I. Taylor.
– In*ane"ly, adv.
In*ane", n.
Definition: That which is void or empty. [R.]
The undistinguishable inane of infinite space. Locke.
Source: Webster’s Unabridged Dictionary 1913 Edition