know inside and out

verb

To know (something or someone) very thoroughly.

“He's still new to their system, but he knows databases inside and out and will understand the rest soon.”

Similar
know backwardsknow back to frontknow like a bookknow like the back of one's hand
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Meanings

verbknow inside and out (third-person singular simple present knows inside and out, present participle knowing inside and out, simple past knew inside and out, past participle known inside and out)

present singular third person knows inside and out · participle present knowing inside and out · past knew inside and out · participle past known inside and out

  1. idiomatictransitiveTo know (something or someone) very thoroughly.

    He's still new to their system, but he knows databases inside and out and will understand the rest soon.

    Synonyms: know backwards, know back to front, know like a book, know like the back of one's hand

Synonyms & antonyms

verbTo know (something or someone) very thoroughly.

Similar
know backwardsknow back to frontknow like a bookknow like the back of one's hand
Also see
know back to frontknow backwardsknow like a bookknow like the back of one's hand

Translations

Danish kende ind og ud
  • kende ind og udknow (something) very thoroughly
Finnish tuntea läpikotaisin
  • tuntea läpikotaisinknow (something) very thoroughly
French connaître sur le bout des doigts
  • connaître sur le bout des doigtsknow (something) very thoroughly
German etwas in- und auswendig kennen, etwas wie die eigene Westentasche kennen
  • etwas in- und auswendig kennenknow (something) very thoroughly
  • etwas wie die eigene Westentasche kennenknow (something) very thoroughly
Polish znać jak własną kieszeń, znać od podszewki
  • znać jak własną kieszeńknow (something) very thoroughly
  • znać od podszewkiknow (something) very thoroughly
Russian знать назубо́к, знать вдоль и поперёк
  • знать назубо́к (znatʹ nazubók)know (something) very thoroughly
  • знать вдоль и поперёк (znatʹ vdolʹ i poperjók)know (something) very thoroughly
Spanish conocerlo como si lo hubiera parido
  • conocerlo como si lo hubiera paridoknow (something) very thoroughly
Swedish känna/kunna något utan och innan
  • känna/kunna något utan och innanknow (something) very thoroughly
Cite this entry
APA

know inside and out. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/know%20inside%20and%20out

MLA

“know inside and out.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/know%20inside%20and%20out. Accessed November 5, 2026.

Chicago

WatkinsX Dictionary, s.v. “know inside and out,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/know%20inside%20and%20out.

Source: know inside and out on Wiktionary, CC BY-SA 4.0.