I smiled if worried about discontentment in career: is – that it? (7,6)
I believe the answer is:
midlife crisis
'i smiled if worried about discontentment' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'career is that it?' is the wordplay.
I cannot quite understand how this works, but
'career' could be 'life' (career can mean someone's life or past) and 'life' is found within the answer.
'is' is found in the answer.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for midlife crisis that I've seen before include "(Male?) menopause" , "Period of panic (when one may not exactly act one's age!)" , "Loss of confidence in one's 40s or 50s, perhaps?" , "Panic often resulting (for men) in ill-advised lifestyle changes" , "An ageing concern?" .)