#1 unstable a. lacking stability or fixity or firmness; "unstable political conditions"; "the tower proved to be unstable in the high wind"; "an unstable world economy". wn
#2 unstable s. [precarious] affording no ease or reassurance; "a precarious truce". wn
#3 unstable s. [mentally ill, unsound] suffering from severe mental illness; "of unsound mind". wn
#4 unstable s. disposed to psychological variability; "his rather unstable religious convictions". wn
#5 unstable s. [fluid] subject to change; variable; "a fluid situation fraught with uncertainty"; "everything was unstable following the coup". wn
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