strengthen

strengthen — verb

1. to add power or strength to a person, object, or situation; or to gain more powe

1.verbtransitive / intransitiveB1
Definition

to add power or strength to a person, object, or situation; or to gain more power or strength yourself

Example

A short walk every morning can strengthen your leg muscles.

collocation: strengthen + body part (muscles, bones, heart)

Hui strengthened her argument by adding more facts to the report.

strengthen + argument / case / position

Common collocations
  • strengthen muscles / bones
  • strengthen the economy
  • strengthen a relationship / bond / tie
  • strengthen an argument / case / position
  • strengthen security / defence
  • strengthen one's resolve / determination
Synonyms
  • reinforce

    add extra support to something already in place; more concrete/physical than strengthen

  • boost

    increase quickly or temporarily; more informal and immediate than strengthen

  • enhance

    improve the quality or value of something; less about raw power and more about refinement

  • fortify

    make stronger against attack or damage; carries defensive or protective overtones

Antonyms
  • weaken

    the direct opposite: to make or become less strong

  • undermine

    gradually weaken something from below or secretly, often in a damaging way

Grammar Patterns

strengthen + noun phrase (transitive)

noun phrase / weather / relationship + strengthen (intransitive)

Usage Note

Can be used transitively (with a direct object: strengthen something) or intransitively (without an object: something strengthens). The intransitive form is common for weather, relationships, and economic conditions.

Common Mistakes

I need to strength my muscles.
I need to strengthen my muscles.
'strength' is a noun; 'strengthen' is the correct verb form.

Word family

Synonym discussion

Sense: verb/1

All five verbs describe making something stronger, but they differ in method and context. Strengthen is the broadest word, covering physical, emotional, and abstract improvement. Reinforce focuses on adding extra support to something already in place — you reinforce a wall, an idea, or a behaviour already present. Boost suggests a quick, often temporary increase — you boost sales, morale, or energy. Fortify carries defensive overtones, like fortifying a building or fortifying your body against illness. Enhance is the most refined: you enhance the quality, flavour, or appearance of something rather than its raw power. For everyday use, strengthen fits most situations. Use boost for short-term improvements, reinforce when strengthening something existing, fortify for protection, and enhance for quality upgrades.

strengthen ↗reinforce ↗boost ↗fortifyenhance ↗

Common collocations

Nouns

  • strengthen relations
  • strengthen ties
  • strengthen links
  • strengthen controls
  • strengthen systems

Adverbs

  • greatly strengthen
  • significantly strengthen
  • further strengthen
  • gradually strengthen
  • steadily strengthen

Phrases

  • help strengthen
  • aim to strengthen
  • designed to strengthen
  • work to strengthen

Prepositions

  • strengthen through
  • strengthen by
  • strengthen over (time)

Etymology

Old EnglishMiddle EnglishEnglish

Strengthen comes from the Middle English word 'strengthen,' formed by adding the verb-making suffix '-en' to the noun 'strength.' The noun 'strength' itself comes from Old English 'strengþu,' related to 'strang' (strong). This '-en' suffix is the same one found in other English verbs like 'lengthen,' 'widen,' and 'deepen' — all meaning 'to cause to become more of the quality named by the adjective or noun.'