indefinite

The adjective indefinite describes something that is vague or not clearly defined: “After injuring her knee in a riding accident, Gloria postponed her vacation for an indefinite period of time.”

You’ve probably noticed that a big chunk of the word indefinite is made up of a familiar word, definite — which means “specific” or “clearly defined.” The two words have common origins in the Latin word definitus (“definite”), but indefinite’s in- prefix gives the word the opposite meaning — "not clearly defined". Indefinite, wonderfully vague and undefined, is your friend for those times when your plans are up in the air (“indefinite plans”) or you don’t want to be pinned down to any particular timeframe (“on indefinite hiatus”).

Definitions of indefinite
1

adj vague or not clearly defined or stated

“must you be so indefinite?”
“amorphous blots of color having vague and indefinite edges”
“he would not answer so indefinite a proposal”
Synonyms:
unclear
not clear to the mind
undefined, vague
not precisely limited, determined, or distinguished
coy
showing marked and often playful or irritating evasiveness or reluctance to make a definite or committing statement
indecisive
not clearly defined
nebulous, unfixed
lacking definition or definite content
noncommittal
refusing to bind oneself to a particular course of action or view or the like
one
indefinite in time or position
indistinct
not clearly defined or easy to perceive or understand
Antonyms:
definite
precise; explicit and clearly defined
clear
readily apparent to the mind
defined
clearly characterized or delimited
certain
definite but not specified or identified
decisive
unmistakable
decided, distinct
recognizable; marked
distinct
easy to perceive; especially clearly outlined
explicit, expressed
precisely and clearly expressed or readily observable; leaving nothing to implication
show more antonyms...

adj not decided or not known

“were indefinite about their plans”
“plans are indefinite
Synonyms:
uncertain
not established beyond doubt; still undecided or unknown