The defining property of any given lexical concept, as each lexical concept has a unique lexical profile. A lexical profile relates to the range of semantic arguments and grammatical constructions with which a given lexical concept conventionally co-occurs and which forms part of the mental knowledge associated with a given lexical concept. The lexical profile thus serves as a principled means of distinguishing lexical concepts conventionally associated with the same form. Two sorts of information form a lexical concept's lexical profile. The first relates to semantic selectional tendencies: the semantic arguments with which a given lexical concept can collocate. The second relates to formal or grammatical selectional tendencies: the formal patterns in which a given lexical concept occurs.

By way of illustration consider the following examples of fly. Lexical concepts are glossed by small capitals in square brackets.

1. The plane/bird is flying (self-propelled (in the sky) aerodynamic motion)
2. The pilot is flying the plane (operation of (in the sky) entity capable of aerodynamic motion)
3. The child is flying the kite (control of (in the breeze) lightweight entity)
4. The flag is flying (suspension of (in the breeze) lightweight object) Unlike nouns, for which a salient grammatical feature is how they are determined, a salient grammatical feature for verbs is transitivity. In terms of formal dependencies then, the hallmark of the lexical concepts which licence the uses of fly in (1) and (4) is the lack of a direct object (an intransitive verb). This contrasts with the lexical concepts which sanction the examples in (2) and (3) which both require a direct object (a transitive verb). This distinction in transitivity fails to distinguish (1) from (4) and (2) from (3). For this we must rely on semantic tendencies. The hallmark of each of these lexical concepts is that they require distinct semantic arguments.

Entities that are not self-propelled, such as tennis balls, cannot be used in this sense (*the tennis ball is flying in the sky).

The lexical concept which underlies the use of fly in (2): (operation of entity capable of aerodynamic motion), is restricted to the operation by an entity which can be construed as an agent, and moreover to entities that can undergo self-propelled aerodynamic motion. Further, the entity must be able to accommodate the agent and thereby serve as a means of transport.

This explains why planes and hot air balloons are compatible with this sense, but entities unable to accommodate an agent are not.

In the case of (control of lightweight entity) as evidenced by the use of fly in (3), this lexical concept appears to be restricted to entities that are capable of becoming airborne by turbulence and can be controlled by an agent on the ground. This lexical concept appears to be specialised for objects like kites and model/remote controlled aeroplanes.

The final lexical concept, glossed as (suspension of lightweight object), selects for entities that can be supported by virtue of air turbulence but remain 'connected to' the ground. This lexical concept applies to flags as well as hair and scarves, which can 'fly' in the wind.