Semantic features,semantic roles and lexical relations

Semantic features: refers to the Word meanings; is the analysis of the word meanings based on meaning postulates and the other semantic components into which the lexical meaning are analyzed.
Examples:
Man is [+HUMAN], [+MALE], [+ADULT]
Woman is [+HUMAN], [-MALE], [+ADULT]
Boy is [+HUMAN], [+MALE], [-ADULT]
Girl is [+HUMAN], [-MALE], [-ADULT]
Intersecting semantic classes share the samefeatures. Some features need not be specifically mentioned as their presence or absence is obvious from another feature.

Semantic Role: A semantic role is the underlying relationship that a participant has with the main verb in a clause. Semantic role is the actual role a participant plays in some real or imagined situation, apart from the linguistic encoding of those situations.
Agent: Agentis the semantic role of a person or thing who is the doer of an event. An agent is usually the grammatical subject of the verb in an active clause. A prototypical agent is conscious, acts with volition (on purpose), and performs an action that has a physical, visible effect.
Theme: Undergoes the action but does not change its state (e.g., We believe in many gods. I have two children. I put thebook on the table. He gave the gun to the police officer.).
Instrument: Used to carry out the action (e.g., Jamie cut the ribbon with a pair of scissors.).
Experiencer: Is the semantic role of an entity (or referent) which: receives, accepts, experiences, or undergoes the effect of an action.
Location: Where the action occurs (e.g., Johnny and Linda played carelessly in the park.).
Source: Wherethe action originated (e.g., The rocket was launched from Central Command. She walked away from him.).
Goal: Where the action is directed towards (e.g., The caravan continued on toward the distant oasis. He walked to school.).

Lexical relations: A lexical relation is a culturally recognized pattern of association that exists between lexical units in a language.
Synonymy: Discovering andunderstanding the use of words which have the lexical relation synonym is important for the accurate and effective choice of words in communication and translation. A synonym lexical relation is a relationship between two or more lexical units which have identical core semantic components and which differ only with respect to their supplemental or peripheral components.
Example:
Stylistic (mostcommon): A lexical unit that has a similar range of reference but is differentiated by speaker intention, the audience, and the situation.
{happy, glad, joyful}
Loanword: A nearly synonymous lexical unit, borrowed from another language to fill what is perceived to be a semantic gap.
The word kabunyan means 'sky' in Tuwali Ifugao, but the word langit which means 'sky' in Tagalog has been borrowedto refer to 'heaven.'
Dialectal: Different lexical units that are part of the vocabulary of different dialects but have very similar ranges of reference.
{flashlight (American English), torch (British English)}
Antonymy: An opposite lexical relation is an association between two lexical units which have the opposite core meanings in some contexts.
Examples:
Complements: Opposites that havemutually exclusive properties. For example, if people are not dead, they must be alive.
{(dead, alive), (true, false), (open, shut), (male, female)}
Antonyms: Opposites that are at two corresponding points or ranges of a scale. For example, if something is not long, it is not necessarily short. There is neutral ground on the scale.
{(long, short), (good, bad), (hot, cold), (warm, cool)}Directional converses: Opposites marking the two directions along an axis.
{(east, west), (up, down), (convex, concave)}

Relational converses: Opposites which specify the relative positions of two entities on opposite sides or poles of a spatial or relational axis.
{(above, below), (in front of, behind)}; {(doctor, patient), (teacher, pupil), (master, servant), (husband, wife)}
Hyponymy: The...