These words are used to state to what extent something applies. Synonyms for 'substantially' include 'very largely', 'mostly', 'to a large extent', or 'almost' : e.g. 'the work has been substantially done' i.e. most of it has been done, it is near completion, it is almost finished. 'Partially' means 'in part', some of it : 'the work is partially done' - some of it has been done [but quite a lot remains] ; 'the area is partially covered' - part of the area is covered.

The term "substantially" means that something completed by a large amount or degree The term "partially" means "not completely". The terms note the degree of compliance: fully compliant, substantially compliant, partially compliant, non-compliant.