IPA: /ˈθɜːroʊˌɡoʊɪŋ/
KK: /ˈθɜroʊˌɡoʊɪŋ/
Complete and thorough in every way; not limited or partial.
The team conducted a thoroughgoing analysis of the data before making their recommendations.
Thoroughgoing → It is formed from "thorough" (from Old English *þurh*, meaning through) and "going" (from Old English *gān*, meaning to go). The word "thoroughgoing" means going through completely or in every aspect.
Think of going 'through' ('thorough') something completely, which is what 'thoroughgoing' means.