slender = slight (slim) + tender.
Such blends are especially frequent in words expressive of sounds or in some other way symbolical, as, for instance:
flurry = fling, flow and many other fl-words + hurry (note also scurry).
gruff = grum, grim + rough.
slide = slip + glide.
troll = trill + roll (in some senses perhaps rather from tread, trundle + roll).
twirl = twist + whirl.
In slang blends abound, e.g.:
tosh (Harrow) = tub + wash. (Sometimes explained as toe-wash.)