Mercury square Lilith (orb 1.7°) creates concrete friction between the two planets. The orb is very tight; this describes a stable character pattern more than a passing reaction.
Here, Mercury in Scorpio in House 6 brings intellect, language, thought, and technique into House 6 (daily work, technique, and bodily discipline), with Scorpio style (intensity, desire, crisis, secrecy, and invisible power); Lilith in Leo in House 3 brings pure ideal, absolute demand, fascination, and refusal of compromise into House 3 (speech, learning, and the close environment), with Leo style (presence, pride, creation, and the wish to be seen).
Concrete friction: this aspect creates tension between thought, speech, obsession, purity demand, and refusal to let go. Visible angle: Lilith near the IC (orb 4.5°) touches an angle; this aspect is easier to notice through private base, family roots, and intimate psychological climate. House 6 (daily work, technique, and bodily discipline) is in friction with House 3 (speech, learning, and the close environment); this can create blockage, inhibition, overreaction, or repeated conflict between the two fields.