why does substandard mean less then standard,but substantial means good enough?

Question

sub par is not good enough...so, shouldn't we say, for example, "the meal was stantial," if it was enough?

Answer 1

Great question. You are wondering why the prefix 'sub' appears to have contradictory meanings.

In fact, in these instances there is no contradiction if you think about the etymology (origin) of the words.

Substance comes from the Latin "substantia" sub means from and stantia means stand or exist, so substance really means from something real, or with a physical presence.

Standard means an acceptable level of something, and sub is used as a simple prefix to mean less than.

Answer 2

This sounds like a quality control issue, when you have items that have to meet certain quality standards and they don't it basically means they are "substandard". Substantial is not a mandatory quality control requirement but it just letting you know that even though it does not meet meet certain standards it still good enough to use at what ever it applies to.