Frank had a meal but hasn't yet a seat (9)
I believe the answer is:
candidate
'hasn't yet a seat' is the definition.
I can't judge whether this definition defines the answer.
'frank had a meal' is the wordplay.
'frank' becomes 'candid' (synonyms).
'had a meal' becomes 'ate' (I've seen this in another clue).
'candid'+'ate'='CANDIDATE'
'but' is the link.
Can you help me to learn more?
(Other definitions for candidate that I've seen before include "Person seeking office or appointment" , "One standing for office" , "Applicant; examinee" , "Job applicant or political aspirant" , "Campaigner" .)