Normal (exact only) Lookup transformations perform exact lookups by joining data in input columns with columns in a reference dataset.
Exact matching return one and only one match in the reference dataset.
Exact lookup matching can use any DTS data type except DT_TEXT, DT_NTEXT, and DT_IMAGE, DT_R4, DT_R8.
In Contrast:
Fuzzy Lookup transformations also join data in input columns with columns in a reference dataset, but also perform data cleaning tasks such as standardizing data(such as addresses and names), correcting data, and providing missing values.
Fuzzy matching return one or more close matches in the reference dataset.
Only input columns with the DT_WSTR and DT_STR data types can be used in fuzzy matching.