She's the perfect candidate for the job, but I need to confirm her 'availability'. [=I need to make sure she is available]
The woman who answered the phone said, “I'm sorry, but Mr. Adams is not 'available' right now. May I take a message?”
He wanted to ask her on a date, but wasn't sure if she was 'available'. [='single']
(..) to interrogate Lady Litton. I'm trying to find out where her husband is. Her husband is in Lugash. - He's been there since Tuesday. - Well, in that case, I will leave on the next available plane. Um, yes, sir, yes, quite, quite. I quite understand what you mean. I'm not arguing with you about that. (..)1975 The Return of the Pink Panther