Object to having invite not guaranteed at first (5)

I believe the answer is:

thing

'object' is the definition.
(an object is a thing or item)

'to having invite not guaranteed at first' is the wordplay.
'at first' suggests taking the first letters.
The initial letters of 'to having invite not guaranteed' is 'THING'.

(Other definitions for thing that I've seen before include "Object; gadget" , "An unnamed object or item" , "Unspecified object" , "Obsession" , "Body" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.