infect
B2Neutral; common in medical, technical, and figurative everyday contexts.
Definition
Meaning
To transmit a disease or harmful microorganism to (a person, organism, or thing).
To contaminate or affect something negatively; to transmit a quality, emotion, or idea to others.
Linguistics
Semantic Notes
Primarily transitive. The figurative use (infect with enthusiasm, fear) is a dead metaphor from the medical sense.
Dialectal Variation
British vs American Usage
Differences
No significant difference in core meaning or usage. Spelling derivatives follow regional patterns (e.g., infected/infecting).
Connotations
Identical. Both carry strong negative connotations in literal use, potentially positive in figurative (e.g., 'infectious laughter').
Frequency
Equally frequent in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
NP infect NP (literal)NP infect NP with NP (literal/figurative)NP be infected by NPNP get infectedVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “Spread like wildfire (related concept)”
Usage
Context Usage
Business
Rare, except in IT ('The malware infected the network') or metaphorically ('His pessimism infected the team').
Academic
Common in medical, biological, epidemiological, and computer science texts.
Everyday
Common in health discussions ('Don't infect me!') and figurative speech ('She infected us with her excitement').
Technical
Precise term in medicine (pathogen-host interaction) and cybersecurity (malware).
Examples
By Part of Speech
verb
British English
- The wound could easily infect if not kept clean.
- One person can infect dozens on the tube during rush hour.
- His bad mood seemed to infect the whole office.
American English
- The virus can infect a cell in minutes.
- Don't go to work and infect everyone in the office.
- Her enthusiasm infected the entire team.
adverb
British English
- N/A (No standard adverb form from 'infect').
American English
- N/A (No standard adverb form from 'infect').
adjective
British English
- N/A (The adjective form is 'infectious' or 'infected').
American English
- N/A (The adjective form is 'infectious' or 'infected').
Examples
By CEFR Level
- Wash your hands so you don't infect others.
- The sick child stayed home.
- Mosquitoes can infect people with malaria.
- His laughter was infectious and made everyone smile.
- The hacker's goal was to infect as many computers as possible with ransomware.
- A sense of panic began to infect the crowd as the news spread.
- The pathogen has evolved to infect its host more efficiently while evading the immune system.
- Cynical attitudes, once confined to a minority, have now infected mainstream political discourse.
Learning
Memory Aids
Mnemonic
Think: IN + FACT. A virus gets IN you and makes you sick as a matter of FACT.
Conceptual Metaphor
BAD INFLUENCE IS A DISEASE / EMOTION/IDEA IS A CONTAGIOUS DISEASE.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid using 'infect' for non-living contamination like water pollution (use 'contaminate').
- The Russian verb 'заражать' is a near-perfect semantic match, including figurative use.
Common Mistakes
- Incorrect: *'The water was infected with chemicals.' (Use 'contaminated').
- Incorrect preposition: *'He infected me by his cold.' (Correct: 'He infected me with his cold.' or 'I was infected by him.')
Practice
Quiz
In which sentence is 'infect' used figuratively?
FAQ
Frequently Asked Questions
'Infect' is used primarily for living organisms (people, animals, cells) being invaded by pathogens. 'Contaminate' is broader, used for making something impure or harmful, often for substances, places, or objects (e.g., contaminated water, food, evidence).
The verb 'infect' itself is neutral but typically has a negative object (disease, fear). The positive connotation comes from the adjective 'infectious' (infectious laughter, enthusiasm), meaning 'spreading readily.'
The main patterns are: 'infect someone/something WITH a disease/virus/feeling' (agent of infection) and 'be infected BY someone/something' (source of infection).
Yes, it is the standard term for malware entering and affecting a computer system (e.g., 'The Trojan infected thousands of PCs').