Put up with old lecturer that's reliable (5)
I believe the answer is:
loyal
'reliable' is the definition.
(I've seen this in another clue)
'put up with old lecturer' is the wordplay.
'put' becomes 'lay' (synonyms).
'up' is a reversal indicator (in down clue: letters go upwards).
'with' is a charade indicator (letters next to each other).
'old lecturer' becomes 'lo' (I can't justify this - if you can you should give a lot more credence to this answer).
'lay' back-to-front is 'yal'.
'yal' after 'lo' is 'LOYAL'.
'that's' is the link.
Can you help me to learn more?
(Other definitions for loyal that I've seen before include "Faithful to country, cause or friend" , "Unwaveringly devoted to friend or cause" , "Steadfast in allegiance" , "Showing enduring firm support" , "Faithful - true" .)