PONDEROUS

weighty

unyielding

slow and laborious because of weight
SYN - heavy, lumbering
"a ponderous yawn"

having great mass and weight and unwieldiness
ANT - lightfooted
"ponderous weapons"

labored and dull
"a ponderous speech"

"He continued to be ponderous in his enacting more green solutions to energy."

"How could he justify this ponderous pace when so many people were dying every minute a decision wasn't made - this was likely to go down as one of the worst moments in President Clinton's term."

"He new he would have to make do with his families ponderous minivan...but even with this he was bound to beat Jimmy to California."