unable
adj.adj. not having the power, skill, or chance to do something. You use it when you cannot complete an action.
adj. lacking the necessary power, ability, or resources to perform a specific action.
She is unable to attend the meeting today.
The pilot was unable to land the plane because of the thick fog covering the runway.
Despite several attempts to restart the server, the technical team remained unable to restore the database before the morning shift began.
From Middle English unable, unabel, unhable, unhabil, equivalent to un- + able.
From Middle English unablen, equivalent to un- + able.
Always followed by a 'to' infinitive when describing the action that cannot be performed.
I am unable of goingI am unable to goUnlike the noun 'inability' or the adjective 'incapable', 'unable' must be followed by a 'to' infinitive, not 'of' + gerund.