Substantial - substantive
Do not confuse the very similar adjectives substantial and substantive. They share a root in the Latin substantia, 'substance', but their uses have diverged - slightly. but significantly. They share a common connotation of 'massive', 'important', 'meaningful', and have similar pronunciations, with the stress on the second syllable: 'subs-TANCH-el' (IPA: /sə (or ʌ) b ˈstæn ʃəl/) and 'subs-TANT-iv', /sə (or ʌ) b ˈstæn tɪv/.
- Substantial is the more physical of the two. The basic meaning is 'composed of, or containing, [a large mass of] [physical] substance'. A well-fed man might be described as having a substantial stomach, and his meal might be a substantial one; buildings in the open countryside should be substantial enough to resist the strongest winds. An estate in the countryside might be called substantial if it spread over many acres, and cost a lot of money. More figuratively, a computer program should be sufficiently substantial to resist hacking attacks.
- Substantive is more concerned with the importance of an idea. The substantive part of an argument is that which is most relevant to the subject at hand. A diplomat, for example, engaged in negotiations may want to reach the substantive point only after more trivial details have been settled; a prosecutor may have charged a defendant with several minor infringements of the law as well as the substantive charge of a major crime.
- There are other, technical, uses in various academic subjects, such as philosophy, medicine (archaically), dyeing, and law. In military circles, a member of the armed forces who has been promoted temporarily (e.g. in the field, in course of an action) will retain the substantive rank achieved beforehand until the temporary promotion is made permanent.
- As a noun, substantive (pronounced with the stress on the first syllable, 'SUB-stant-iv', IPA: /ˈsʌb stæ (or ə) n tɪv/) was until late in the nineteenth century the most common term in grammar for what is now usually, and in AWE almost always, called a noun: "the part of speech which is used as the name of a person or thing" (OED, 2020), i.e. a substantial matter. See also substantive (grammar).