thicken

verbs

make thick or thicker
"Thicken the sauce"; "inspissate the tar so that it becomes pitch"
inspissate, thicken
is derived from
thickener
is derived from
thickening
antonym
thin
become thick or thicker
"The sauce thickened"; "The egg yolk will inspissate"
inspissate, thicken
antonym
thin
make viscous or dense
"thicken the sauce by adding flour"
inspissate, thicken
is derived from
thickener
is derived from
thickening