Oddly appearing if nobody has returned for the kids, funnily (4)
I believe the answer is:
yoof
'the kids funnily' is the definition.
(humorous or informal term for 'youth')
'oddly appearing if nobody has returned' is the wordplay.
'oddly appearing' means one should take alternating letters (letters in odd-numbered positions).
'has returned' shows that the letters should be reversed in order.
'if'+'nobody'='ifnobody'
The alternating letters of 'ifnobody' are 'fooy'.
'fooy' reversed gives 'YOOF'.
'for' acts as a link.
(Other definitions for yoof that I've seen before include "Young people humorously" , "Juveniles" , "Teenagers" , "Youngsters" .)