Synonyms for invalid
- adjective
Most common
Synonyms by meaning
Adjective
1. Unsound
unsound, fallacious, illegitimate, spurious, false, untrue, bad, disabled, disallowed, sick, unhealthy, infirm, feeble, frail, indefensible, sickly, weakly, valetudinarian, nonvalid, ailing, valetudinary dated
2. Null
Definitions
- adj. 1
Not valid; not true, correct, acceptable, or appropriate.
This invalid contract cannot be legally enforced.
- adj. 2
Suffering from disability or illness.
Related words
- Word family
- invalidhood invalidism
Example sentences
- illegitimate The king had numerous illegitimate children with her.
- spurious His books were filled with spurious arguments.
- unsound Your position is unprovable and unsound.
- fallacious Her line of reasoning is attractive, but ultimately fallacious.
- expired Your session expired, please log yourself back in.
Popularity over time
| Word | 1850 → 2019 | Trend |
|---|---|---|
| invalid | falling | |
| illegitimate | steady | |
| spurious | falling | |
| unsound | falling | |
| fallacious | falling | |
| expired | falling |
Use in printed books, per decade from 1850 to 2019.
By length
- 3 letters
- bad1
- 4 letters
- sick1, void1, null1
- 5 letters
- false1, frail1
- 6 letters
- untrue2, feeble2, weakly2, ailing2, sickly2, infirm2
- 7 letters
- expired2, unsound2
- 8 letters
- disabled3, spurious3, nonvalid
- 9 letters
- unhealthy3, sophistic
- 10 letters
- disallowed3, fallacious3
- 12 letters
- illegitimate5, indefensible5, valetudinary
- 14 letters
- valetudinarian
The small number after each word is its number of syllables (untrue2 = 2 syllables).