build up

Verb

build up (third-person singular simple present builds up, present participle building up, simple past and past participle built up)

1. To erect; to construct.
   • Near-synonym: build out
   • The motor bogies are built up from plates and rolled sections, and have cast-steel, one-piece axleguards, with manganese liners.1956 December, “New Electric Trains for Mersey Lines”, in Railway Magazine, page 850

   Synonyms:

   assemble, build, put together, artifice, betimber, compile, construct, edify, erect, extruct

   Antonyms:

   take down, tear down, disassemble

2. To close up by building.
   • to build up a door

   Synonyms:

   close, close off, close up, cover, cover up, enclose, shut, shut in, shut off, shut up

3. (idiomatic, intransitive, transitive) To accumulate: to increase incrementally or continually.
   • Ever since the secretary left, the letters in my inbox have started to build up.
   • The first English Electric units were not fitted with an anti-slip brake, but a hurried consultation of the wiring diagram showed that it should be possible to hold in the low-voltage anti-slip relay for long enough to let speed build up without cutting off the motor current.1962 April, R. K. Evans, “The Acceptance Testing of Diesel Locomotives”, in Modern Railways, page 268

   Synonyms:

   pile up, amass, heap up, accumulate, agglomerate, cumulate, heap, mound, pile, rack up

4. (idiomatic, transitive) To strengthen.
   • They had to build up their fortress to protect against attack.
   • "It took it out of me, though. I'm a rag this morning." "They work you too hard, dear. I'll take you to Margate and build you up." "Well, maybe at Easter we could do a week."1925 July – 1926 May, A[rthur] Conan Doyle, “(please specify the chapter number)”, in The Land of Mist (eBook no. 0601351h.html), Australia: Project Gutenberg Australia, published April 2019
5. In solitaire card games, to place a card over another card of lower value. (e.g., place 5♦ over 4♣)

   Antonyms:

   build down