invariable

/ɪnˈvɛriəbəl/

/ɪnˈvɛriəbəl/

Other forms: invariables

Use the adjective invariable to describe something that's unlikely to change, such as your invariable custom of eating deep-dish pizza every Saturday.

You can hear the word vary in invariable. Something that varies changes or is made up of different kinds of things. When you add the prefix in-, meaning "not," and the adjective suffix -able, you get an adjective to describe something that's not able to vary or change. Synonyms for invariable include constant, fixed, and immutable. Someone who's invariable in her habits may seem predictable and boring on the one hand, and steady and reliable on the other.

Definitions of invariable

1. adjective

   not liable to or capable of change
   “an invariable temperature”

   “an invariable rule”

   “his invariable courtesy”

   synonyms:

   consistent

   (sometimes followed by `with') in agreement or consistent or reliable

   constant

   steadfast in purpose or devotion or affection

   changeless, constant, invariant, unvarying

   unvarying in nature

   hard-and-fast, strict

   (of rules) stringently enforced

   invariant

   unaffected by a designated operation or transformation

   antonyms:

   variable

   liable to or capable of change

   inconsistent

   displaying a lack of consistency

   inconstant

   likely to change frequently often without apparent or cogent reason; variable

   changeable, uncertain, unsettled

   subject to change

   covariant

   changing so that interrelations with another variable quantity or set of quantities remain unchanged

   multivariate

   pertaining to any procedure involving two or more variables

   protean

   taking on different forms

   shifting

   continuously varying

   variant

   exhibiting variation and change

   versatile

   changeable or inconstant
2. noun

   a quantity that does not vary
   synonyms: constant, constant quantity

   types:

   parameter, parametric quantity

   a constant in the equation of a curve that can be varied to yield a family of similar curves

   degree of freedom

   one of the minimum number of parameters needed to describe the state of a physical system

   type of:

   quantity

   the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable