1.
Something that is ~ is unlikely to be true or to happen.
...a highly ~ coincidence...
= unlikely
? probable, likely
ADJ: oft it v-link ADJ that
improbability (improbabilities)
...the improbability of such an outcome.
N-VAR
2.
If you describe something as ~, you mean it is strange, unusual, or ridiculous.
On the face of it, their marriage seems an ~ alliance.
= unlikely
ADJ
improbably
The sea is an improbably pale turquoise...
ADV: ADV adj, ADV with v, ADV with cl