Definition of borderline
(Entry 1 of 2)
1a
: being in an intermediate position or state : not fully classifiable as one thing or its opposite
a borderline state between waking and sleeping
b
: not quite up to, typical of, or as severe as what is usual, standard, or expected
borderline intelligence borderline hypertension
c
: characterized by psychological instability in several areas (such as interpersonal relations, behavior, and identity) but only with brief or no psychotic episodes
a borderline personality disorder
2
: situated at or near a border
a borderline town
borderline
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Merriam-Webster unabridged
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Time Traveler for borderline
The first known use of borderline was in 1907
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