invalid
- 01 B1 Intermediate
adj.not true, correct, or acceptable according to the rules.
adj.lacking legal force or logical validity; null and void.
Simple“The website said my password was invalid because I used the wrong characters.”
In context“The contract was declared invalid by the court because one of the signatures had been forged.”
UsageThe stress is on the second syllable: in-VAL-id.
PitfallThe password was unvalid. The password was invalid.The prefix for 'valid' is 'in-', not 'un-'.
- 02 C1 Advanced
v.to officially allow someone to leave the army or a job because they are too sick to work.
v.to remove someone from active duty, particularly in a military context, due to injury or chronic ill health.
Simple“The soldier was invalided out of the army after losing his sight in the war.”
In context“He was eventually invalided home after contracting a tropical fever that left him unable to perform his duties.”
UsageUsually appears in the passive voice as 'to be invalided out'.
Teacher's tipThis is a specialized term mostly found in historical or military literature.
From in- + valid.
From Middle French invalide, from Latin invalidus (“infirm, weak”), from in- (“not”) + validus (“strong”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.