weighty
wei-ghty
adjective
Having considerable physical mass or heaviness; difficult to lift.
"The old oak chest was extremely weighty."
adjective
Of great importance, seriousness, or influence; requiring careful consideration.
"We discussed many weighty matters at the meeting."
Thesaurus
Synonyms: important, grave, of import, heavy, grievous, fat, obese, rotund, corpulent, persuasive, telling, cogent
Antonyms: weightless