Tardy person is bad for morale etc. (9)
I believe the answer is:
latecomer
'bad for morale etc' is the definition.
I can't tell whether this definition defines the answer.
'tardy person' is the wordplay.
'tardy' becomes 'late' (synonyms).
'person' becomes 'comer' (comer is a kind of person).
'late'+'comer'='LATECOMER'
'is' is the link.
Can you help me to learn more?
(Other definitions for latecomer that I've seen before include "one's a poor timekeeper" , "Delayed arrival" , "Recent or tardy arrival" , "One who arrives tardily, not punctually" , "Perhaps one held up" .)