Likely (3)
'likely' is the definition.
(I know that likely can be written as probable)
This is all the clue.
(Other definitions for probable that I've seen before include "Likely to be the case" , "on the cards" , "Seeming to have a good chance of happening" , "Person most likely" , "Likely to happen but not certain" .)
'likely' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for apt that I've seen before include "Suitable, appropriate" , "Tending" , "Suitable or likely" , "suitable for the circumstances" , "Tap (anag.)" .)
'likely' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for liable that I've seen before include "legally obliged, held responsible" , "Likely" , "Legally answerable" , "Legally obligated" , "'Responsible, answerable (6)'" .)
'likely' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for on the cards that I've seen before include "Quite likely" , "Greetings may be" , "Quite possible (colloq.)" , "Likely to happen" , "to have a PAYE job?" .)