glue and lacquer; inseparable bond
Literary metaphor for an extremely close, inseparable relationship, like glue and lacquer that cannot be separated once joined. The literal meaning 'glue and lacquer' is the basis for the figurative use.
Their friendship is like an inseparable bond of glue and lacquer.
古典では、夫婦の仲を膠漆にたとえることがある。
In classical literature, the relationship between husband and wife is sometimes likened to glue and lacquer.