lisp

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A speech defect or mannerism characterized by mispronunciation of the sounds (s) and (z) as (th) and (th).
• noun A sound of or like a lisp.
• intransitive verb To speak with a lisp.
• intransitive verb To speak imperfectly, as a child does.
• intransitive verb To pronounce with a lisp.

from The Century Dictionary.

• noun The habit or act of lisping, as in uttering th for s, and Ŧh for z; an indistinct utterance, as of a child.
• To pronounce the sibilant letters s and z imperfectly, as by giving the sound of th (as in thin) or Ŧh (as in this, either.)
• To speak imperfectly, as in childhood; make feeble, imperfect, or tentative efforts at speaking; hence, to speak in a hesitating, modest way.
• To pronounce with a lisp or imperfectly.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To pronounce with a lisp.
• transitive verb To utter with imperfect articulation; to express with words pronounced imperfectly or indistinctly, as a child speaks; hence, to express by the use of simple, childlike language.
• transitive verb To speak with reserve or concealment; to utter timidly or confidentially.
• intransitive verb To pronounce the sibilant letter s imperfectly; to give s and z the sound of th; -- a defect common among children.
• intransitive verb To speak with imperfect articulation; to mispronounce, as a child learning to talk.
• intransitive verb To speak hesitatingly with a low voice, as if afraid.
• noun The habit or act of lisping. See lisp, v. i., 1.
• noun (Computers) a high-level computer programming language in which statements and data are in the form of lists, enclosed in parentheses; -- used especially for rapid development of prototype programs in artificial intelligence applications .

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The habit or an act of lisping.
• verb To pronounce the sibilant letter ‘s’ imperfectly; to give ‘s’ and ‘z’ the sounds of ‘th’ (IPA: /θ / ð/) — a defect common amongst children.
• verb To speak with imperfect articulation; to mispronounce, as a child learning to talk.
• verb To speak hesitatingly and with a low voice, as if afraid.
• verb To pronounce with a lisp.
• verb To utter with imperfect articulation; to express with words pronounced imperfectly or indistinctly, as a child speaks; hence, to express by the use of simple, childlike language.
• verb To speak with reserve or concealment; to utter timidly or confidentially; as, to lisp treason.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a flexible procedure-oriented programing language that manipulates symbols in the form of lists
• noun a speech defect that involves pronouncing `s' like voiceless `th' and `z' like voiced `th'
• verb speak with a lisp