A planet is defined as peregrine when it has no level of rulership over its position. That is, it is not placed in the sign(s) that it rules, nor those where it is exalted, nor does it rule the triplicity, or the terms or face where it is located. [See: Ptolemy's Table of Essential Dignities]
The word 'Peregrine' comes from a Latin term meaning 'alien' or 'foreigner' (pereger = beyond the borders, ager = land, i.e., 'beyond one's own land'). In old English, to 'peregrinate' means to wander far from home.
Such a planet is therefore seen as having little influence or control over its environment. In symbolic terms, it describes a drifter - someone with no title or stake in his or her environment. In matters of theft, for example, peregrine planets fall under suspicion in the same way that strangers are often viewed with suspicion. In other matters it might portray someone who lacks a clear sense of focus, a sense of feeling 'lost' or on the outside of community thinking; or an inability to identify clear goals or offer resolute commitments to others.
Mutual reception does not stop a planet being defined as peregrine, although it will of course influence the description of how the planet operates.
For more details see Understanding Planetary Dignity especially part 4: Essential Debility.