ruck vs ruckle

ruck is a noun but ruckle is not a noun.

Word	Noun	Adjective	Verb	Adverb
ruck	Yes	No	Yes	No
ruckle	No	No	Yes	No

As verbs, ruckle is a hypernym of ruck; that is, ruckle is a word with a broader meaning than ruck:

ruck: become wrinkled or drawn together
ruckle: make wrinkles or creases on a smooth surface; make a pressed, folded or wrinkled line in; `crisp' is archaic

Other hypernyms of ruck include crease, crinkle, crisp, scrunch, scrunch up, wrinkle.

ruck (noun)	ruckle (noun)
a crowd especially of ordinary or undistinguished persons or things
an irregular fold in an otherwise even surface (as in cloth)

ruck (verb)	ruckle (verb)
become wrinkled or drawn together	make wrinkles or creases on a smooth surface; make a pressed, folded or wrinkled line in; `crisp' is archaic
	make a hoarse, rattling sound