Lame means walking badly because a leg is injured or weak. A horse that pulls up lame halfway round the field, a dog holding one paw off the ground, someone hobbling to the sofa on a swollen ankle.
The everyday use now has nothing to do with legs: a lame excuse is a weak one, and a lame joke is one that lands with a thud. Americans stretch that further into "boring" — a lame party, a lame film. Be careful with people: calling a person lame is offensive today, and the leg sense has retreated to animals, especially horses, where "go lame" and "pull up lame" are the standard phrases. A lame duck is a leader whose term is running out and who has lost the power to act. The noun is lameness, and the verb to lame — to make lame — lives mostly in old writing.
1adjectivelameUnable to walk properly because of an injured or weak leg.
“The mare went lame at the second fence and had to be walked home.”
synonyms: limping, hobbling
2adjectivefeebleWeak and unconvincing.
“That is a lame argument and you know it.”
synonyms: feeble, weak, unconvincing
3adjectiveboringBoring or disappointing (informal).
“The party was lame and everyone had left by ten.”
Too few real examples of this word to estimate which sense is commonest.
Lame is old and barely changed: Old English lama, from Proto-Germanic *lamaz, both meaning exactly what lame means. Behind them sits a Proto-Indo-European root *h₃lemH-, "to tire; to break" — a leg that has given out. The modern "that's a lame excuse" is the same picture moved indoors: an argument that cannot stand up.
Proto-Indo-European
*h₃lemH- — to tire; to break
Proto-Germanic
*lamaz — lame
Proto-West Germanic
*lam
Old English
lama — lame
Middle English
lame
English, today
lame
From Middle English lame, from Old English lama (“lame”), from Proto-West Germanic lam, from Proto-Germanic lamaz (“lame”), from Proto-Indo-European h₃lemH- (“to tire; to break”).
Etymology from Wiktionary, CC BY-SA