大概
dàgài · HSK 3
approximately
大 (big) + 概 (general/outline) = the big outline → roughly, approximately
概 carries the sense of a general summary or gist (as in 概念 concept, 概况 overview). Pair it with 大 (big) and you get the broad-strokes meaning: probably, approximately, in general terms.
大 — pictograph of a person with arms outstretched
大 is a pictograph showing a person standing with arms and legs spread wide. The outstretched arms suggest 'big' or 'great', extending from the literal image of a large stance to abstract meanings like important or grand. It is one of the oldest characters, found on oracle bones.