Valid but illicit
Valid but illicit and valid but illegal are descriptions applied in Roman Catholicism to an unauthorized celebration of a sacrament that nevertheless has effect.
Validity is presumed whenever an act is placed "by a qualified person and includes those things which essentially constitute the act itself as well as the formalities and requirements imposed by law for the validity of the act".
Canon law also lays down rules for lawful placing of the act.
Holy orders - All bishops are able to ordain a deacon, priest, or bishop. In the sacrament of holy orders, a valid but illicit consecration / ordination, as the name suggests, is an ordination in which a bishop uses his valid ability to ordain someone a bishop without having first received the required authorization. The same would apply to a bishop's ordaining of a man who has not undergone and completed necessary seminary schooling, as required by canon law. The bishop is then acting in a manner deemed illicit or illegal.
(Photo above is Roman Catholic Cardinal Sebastiao Leme da Silveria Cintra. with Roman Catholic Bishop Carlos Duarte Costa.
A Catholic bishop who consecrates someone to the episcopate without a mandate from the Pope is automatically excommunicated according to canon law even if his ordination may be considered valid, a true bishop.
The person who receives consecration from him is also automatically excommunicated.
The excommunication can be lifted by only the Holy See. IF the Holy See has the authority to place such. in the case of many Catholic & Orthodox Churches established this is not the case.
The photo opposite is the Roman Catholic Bishop Carlos Duarte Costa who has just consecrated Catholic Bishop Luis Fernando Castillo Mendez in 1948 who in turn later consecrated at the Cathedral in Brazil, Bishop James Atkinson-Wake under a Patriarchal Mandate.
In the 20th century, Archbishop Marcel Lefebvre is said to have earned automatic excommunication for his valid but illicit ordinations of four bishops without a papal mandate. However, his defenders argue that he acted under grave fear, an excuse allowed by to canon law to avoid automatic excommunication. After Lefebvre's death, the Holy See, on 21 January 2009, lifted the excommunication of the four bishops.
VALID BUT ILLIICIT - The illicitness and the validity of Sacraments are canonical terms used to describe the effectiveness of the sacrament.
Illicit means, roughly, illegal. In the case of a Sacrament, it means performed in a way that is not permitted by the rules or laws of that specific Church. (But the sacrament did happen). The term Illicit can also be used to refer to actions not done in accordance with the established norms.
Invalid means the Sacrament did not happen at all. There is some defect in matter, form or intention. Question of validity occurs only for a Sacrament.
It seems like another way to say this would be that "licit" and "illicit" refers to the performance of the action, where as "valid" and "invalid" refer to the result.