well-grounded (adj.)

• adamantine
• admissible
• authoritative
• binding
• bulky
• calculable
• cogent
• confirmed
• consistent
• credible
• deep-laid
• deep-rooted
• deep-seated
• deep-set
• dense
• dependable
• durable
• embedded
• embossed
• enduring
• engraved
• entrenched
• established
• etched
• faithful
• fast
• firm
• good
• graven
• hard
• heavy
• implanted
• impressed
• ingrained
• ingrown
• inveterate
• invincible
• inwrought
• just
• justifiable
• lasting
• lawful
• legal
• legitimate
• logical
• massive
• old-line
• plausible
• predictable
• rational
• reasonable
• reliable
• rooted
• rugged
• sane
• secure
• self-consistent
• sensible
• set
• settled
• solid
• sound
• stabilized
• stable
• staunch
• steadfast
• steady
• stout
• strong
• sturdy
• substantial
• sufficient
• sure
• tough
• trustworthy
• trusty
• unfailing
• unyielding
• valid
• vested
• weighty
• well-educated
• well-founded
• well-informed
• well-made
• well-read
• well-set
• wholesome