Key
Key adjective - Coming before all others in importance.
Substantial and key are semantically related In some cases you can use "Substantial" instead an adjective "Key".
Substantial
Substantial adjective - Having great meaning or lasting effect.
Usage example: substantial changes to the school dress code that made a lot of people unhappy
Key and substantial are semantically related in important topic. Sometimes you can use "Key" instead an adjective "Substantial".
Mutual synonyms
Both words in one sentence
- Glad I Thought of It is a more low key variation of the trope, with the thief stealing an idea rather than something more substantial.
Source: Stealing the Credit -
You can notice that the gap between the top of the spines and the upper 'shelf' is covered by a leather flap and the key hole is far more substantial than for the glass doors of the real bookshelves.
Source: Book Safe -
The "elbow-length or longer" part is the key; gloves which cover a substantial portion of the forearm, up to just below the elbow, can legitimately be called "long gloves" or "evening gloves", but never "Opera Gloves".
Source: Useful Notes / Opera Gloves
Cite this Source
Substantial and Key. (2016). Retrieved 2026, August 16, from https://thesaurus.plus/related/key/substantial
Key & Substantial. N.p., 2016. Web. 16 Aug. 2026. <https://thesaurus.plus/related/key/substantial>.
Substantial or Key. 2016. Accessed August 16, 2026. https://thesaurus.plus/related/key/substantial.
Google Ngram Viewer shows how "key" and "substantial" have occurred on timeline