Use the adverb obtrusively to mean "in a noticeable way." You could describe your brother's enormous television as stretching obtrusively across his entire living room wall, for example.
Something is done obtrusively when in gets in the way or is glaringly obvious. Cell phone towers often loom obtrusively above fields and forests, and annoying people tend to talk obtrusively throughout movies. Obtrusively comes from the adjective obtrusive, which in turn is rooted in the Latin word obtrudere, "to thrust upon or to press into," from ob, "toward," and trudere, "to thrust."