Leading Question. A leading question is not necessarily an important one; it is one that is so framed as to suggest, or lead to, the answer desired. Few others than lawyers use the term correctly.
Lease. To say of a man that he leases certain premises leaves it doubtful whether he is lessor or lessee. Being ambiguous, the word should be used with caution.
Leave for Go away. "He left yesterday." Leave is a transitive verb; name the place of departure.
Leave for Let. "Leave it alone." By this many persons mean, not that it is to be left in solitude, but that it is to be untouched, or unmolested.
Lengthways for Lengthwise.
Lengthy. Usually said in disparagement of some wearisome discourse. It is no better than breadthy, or thicknessy.
Leniency for Lenity. The words are synonymous, but the latter is the better.
Less for Fewer. "The regiment had less than five hundred men." Less relates to quantity, fewer, to number.
Limited for Small, Inadequate, etc. "The army's operations were confined to a limited area." "We had a limited supply of food." A large area and an adequate supply would also be limited. Everything that we know about is limited.
Liable for Likely. "Man is liable to err." Man is not liable to err, but to error. Liable should be followed, not by an infinitive, but by a preposition.