Learn English: How to stay warm in winter?

op-shop noun [ C ] UK ​ /ˈɒp.ʃɒp/ //awp shop// US ​ /ˈɑːp.ʃɑːp/ australian english

informal for opportunity shop

opportunity shop noun [ C ] UK ​ /ɒp.əˈtjuː.nə.ti ˌʃɒp/ US ​ /ɑː.pɚˈtuː.nə.t̬i ˌʃɑːp/ informal op-shopaustralian english

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a shop in which a charity sells all types of used goods that are given by the public, or in which they sell new goods, to make money for the work of the charity

charity shop noun [ C ] UK ​ /ˈtʃær.ɪ.ti ˌʃɒp/ US ​ /ˈtʃer.ɪ.t̬i ˌʃɑːp/ uk

a shop in which a charity sells all types of used goods that are given by thepublic, or in which they sell new goods, to make money for the work of the charity

woolly adjective US also wooly uk ​ /ˈwʊl.i/ //'wuul.i/ us ​ /ˈwʊl.i/

woolly adjective (OF WOOL)
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› made of wool, or made of something that looks like wool:
a woolly hat/jumper

thermal noun (CLOTHES)

thermals [ plural ]

› informal for thermal underwear


thermal underwear noun [ U ] uk ​ /ˌθɜː.məl ˈʌn.də.weər/ us ​ /ˌθɝː.məl ˈʌn.dɚ.wer/ informal thermals
  
         ​ › underwear that has been specially designed to keep you warm


underwear noun [ U ] uk ​ /ˈʌn.də.weər/ us ​ /ˈʌn.dɚ.wer/

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B1 clothes worn next to the skin, under other clothes

Examples

• lacy underwear
• I had to strip down to my underwear for my medical examination.

rug noun [ C ] uk ​ /rʌɡ/ //rraagg/ us ​ /rʌɡ/
      
B1 a piece of thick heavy cloth smaller than a carpet, used for covering the floor or for decoration:
My dog loves lying on the rug in front of the fire.
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› a soft cover that keeps you warm or comfortable
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› slang for toupée

More examples
The floor was partly covered with a dirty old rug.
She tripped over the rug.

jumper noun [ C ] uk ​ /ˈdʒʌm.pər/ us ​ /ˈdʒʌm.pɚ/

jumper noun [ C ] (CLOTHES)
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A2 UK a piece of clothing with long sleeves that is usually made from wool, is worn on the upper part of the body and does not open at the front:
a red woolly jumper

Compare
sweater

sweater noun [ C ] uk ​ /ˈswet.ər/ us ​ /ˈswet̬.ɚ/
  
         
A2 UK also jumper a piece of clothing, typically with long sleeves and made from wool, that is worn on the upper part of the body:
Put a sweater on if you're cold.
a V-necked sweater

Credit to A+