reliable

reliable — adjective

1. A reliable person, machine, or system always does what you expect, so you can tr

1.adjectiveB1
Definition

A reliable person, machine, or system always does what you expect, so you can trust them completely — for example, a reliable car starts every morning without fail, and a reliable colleague never misses a deadline.

Example

Minh trusts Valentina with his cat because she is a reliable neighbour who keeps promises.

collocation: reliable + role noun (neighbour/friend/colleague)

Adaeze's old washing machine is still reliable after ten years of heavy use.

collocation: reliable + machine/appliance

Common collocations
  • reliable car
  • reliable friend
  • reliable service
  • reliable worker
  • reliable method
  • reliable colleague
  • reliable equipment
Synonyms
  • dependable

    almost identical in meaning; 'dependable' is slightly more common for people, 'reliable' for machines

  • trustworthy

    stronger emphasis on honesty and moral integrity rather than consistent performance

  • trusty

    slightly old-fashioned or playful; often used for objects (trusty bike, trusty knife)

Antonyms
  • unreliable

    direct opposite; describes people or things that cannot be trusted

  • undependable

    less common but means the same as unreliable

Grammar Patterns

attributive: reliable + noun

predicative: be + reliable

Usage Note

Frequently used for both people (a reliable worker) and objects (a reliable car). For people, the focus is on consistent performance rather than moral character — a reliable colleague does the work well even if they are not especially warm or friendly.

Common Mistakes

My car is reliable because it never starts in cold weather.
My car is reliable because it always starts, even in cold weather.
'reliable' describes consistent positive behaviour; the explanation must match the positive meaning.

2. Information, data, or news that is reliable comes from facts that someone has ca

2.adjectiveB2
Definition

Information, data, or news that is reliable comes from facts that someone has carefully checked, so you can trust that it is correct — for example, a reliable weather report from the national weather centre.

Example

Faisal only reads news from reliable sources that check their facts before publishing.

collocation: reliable + source

The data from Amelia's experiment was reliable because she repeated it three times.

collocation: reliable + data/results

Common collocations
  • reliable source
  • reliable information
  • reliable data
  • reliable report
  • reliable evidence
  • reliable statistics
  • reliable forecast
Synonyms
  • accurate

    focuses on exactness and precision rather than trustworthiness

  • credible

    suggests something deserves to be believed because of supporting evidence or a trustworthy source

  • authoritative

    implies the information comes from an official or expert source that can be trusted

Antonyms
  • unreliable

    direct opposite — cannot be trusted to be correct

  • questionable

    suggests doubt about truthfulness without claiming it is definitely wrong

Grammar Patterns

attributive: reliable + information noun

predicative: information/data + be + reliable

Usage Note

Common with nouns related to data, news, research, and reports. This sense does not usually apply to opinions or personal judgments — you would not describe someone's taste in music as 'reliable'.

Common Mistakes

He gave me a reliable opinion about which jacket looks better.
He gave me an honest opinion about which jacket looks better.
'reliable' for information means factually correct, not subjectively honest or thoughtful.

reliable — noun

Word family

Synonym discussion

Sense: adjective/1

Dependable is the closest synonym to reliable and they are often interchangeable, though reliable is slightly broader and more common for machines and systems. Trustworthy adds a strong moral or ethical layer — a trustworthy person tells the truth even when it is difficult, while a reliable person simply does what they say they will do. Trusty has a warmer, slightly old-fashioned or humorous tone (e.g., 'my trusty bicycle') and is less common in formal writing. Loyal refers to faithfulness to a person, group, or cause rather than to consistent performance — a loyal friend stands by you, while a reliable friend shows up when promised. For example, 'The restaurant's reliable chef never burns a steak' focuses on skill, whereas 'the restaurant's loyal chef worked there for twenty years' focuses on commitment.

dependable ↗trustworthy ↗trustyloyal ↗

Common collocations

Nouns

Adverbs

  • extremely reliable
  • very reliable
  • quite reliable
  • fairly reliable
  • generally reliable
  • not entirely reliable
  • usually reliable

Phrases

  • a reliable source of
  • reliable as ever
  • reliable enough to

Prepositions

  • reliable in (a situation)
  • reliable for (a task)
  • reliable at (doing something)

Etymology

LatinOld FrenchEnglish

Reliable was formed in English around the 1560s by adding the suffix '-able' (meaning 'capable of') to the verb 'rely'. The verb rely comes from Old French 'relier' (to fasten, bind together), which traces back to Latin 'religare' — from 're-' (back) and 'ligare' (to bind). The original image is of something you can bind yourself to or lean on for support.