in the midst of busyness; while busy
Often used in set phrases like 忙中閑あり (finding a moment of leisure in the midst of busyness). Rarely used as a standalone noun in modern Japanese.
Even in the midst of busyness, there are moments of leisure; I'd like to relax with a cup of tea once in a while.
finding leisure in the midst of busyness
Compound of 忙 (busy) and 中 (middle, in the midst of). The exact historical derivation is uncertain, but the word is formed from classical Chinese-style compounding.