Dictionary.com
Thesaurus.com
Synonyms

through thick and thin

Cultural  
  1. To stay with someone or something “through thick and thin” is to persevere through good times as well as bad: “She stood beside her friend through thick and thin.”


through thick and thin Idioms  
  1. Despite all obstacles or adversities, as in She promised to stand by him through thick and thin. This term alludes to penetrating a forest with both thick and sparse undergrowth. Today it is nearly always used with the idea of supporting something or someone in all circumstances, as in the example. [Late 1300s]