junior
younger
subteen
two
twos
second cousin once removed
nibbling
younghead
knee baby
bovver bird
titch
twinling
twinsie
half-cousin
teenager
mersister
half
feely
coeval
contemporary
pigeon pair
ephebe
halfling
rugrat
our kid
rug monkey
male sibling
cotwin
second cousin
age-mate
sylphid
lanneret
pretween
adult third culture kid
half blood
tacker
preteen
feely-omi
sister
first cousin once removed
juvenile
grandchild
second grader
nonidentical
brother german
first cousin twice removed
elder
three
half-uncle
paternal cousin
baby of the family
youngest
youthman
half niece
catworm
fraternal
half-first cousin
maternal cousin
tweenie
sesquiple first cousin
irregular double first cousin
lastborn
uterine sibling
littlie
duo
shaver
birthmate
little boy
third cousin
cousinette
kipper
loon
peanut
little sister
little brother
big brother