Find Antonyms
unsound Antonyms
Opposite of unsound
Because the opposite of unsound shifts with each meaning, the 18 antonyms and opposite words below are separated across 3 exact definitions and ranked by contrast strength.
• adjective (Context 1)
Not based on reliable evidence, solid reasoning, or valid principles; flawed or ill-founded.
Usage Example
"The committee rejected the proposal because it relied on financially sound assumptions."
Strongest
sound
valid
Strong
logical
reliable
solid
well-founded
rational
cogent
• adjective (Context 2)
In poor physical condition; structurally weak, damaged, or unsafe.
Usage Example
"Engineers declared the old wooden bridge structurally sound after the severe flooding."
Strongest
sound
solid
sturdy
Strong
stable
intact
secure
robust
• adjective (Context 3)
Not in good physical or mental health; unwell or impaired (especially in the legal phrase 'of unsound mind').
Usage Example
"The court ruled that the testator was of sound mind when the final will was signed."
Strongest
sound
sane
healthy
Strong
lucid
well
fit
Similar words to unsound
Words similar to unsound shift depending on context. Common synonyms include:
flawed
unsafe
invalid
unhealthy
unstable
fallacious
unwell
ill-founded
• Nearby Words
Cite this Entry
Wordmom. (2026). Antonyms for Unsound. In Wordmom Thesaurus. Retrieved Nov 5, 2026, from https://wordmom.com/antonyms/unsound